Pack Check
Paste the numbers off your car deal and find out if the payment got packed with fees you never agreed to.
PackCheck
Paste the numbers off your car deal and find out if the payment got packed with fees you never agreed to.
Date: 2026-10-15 Form factor: web app Status: Prototype
What it is
PackCheck takes the loan terms and add-ons from a car deal — financed amount, APR, term, the payment the dealer quoted you — and runs the math a finance office hopes you won't. It recalculates what the payment should be from the loan terms alone, flags the gap if the dealer's number is higher, and checks your add-ons against a list of the items regulators keep citing in packing complaints. If you bought in California, it also checks your deal against the state's new all-in-pricing and cancellation rules. At the end it writes a dispute letter with your numbers already filled in.
Who it serves
Anyone who just signed a car deal, or is about to, and has a nagging feeling the monthly payment doesn't match what they thought they agreed to. The tool is built for someone without finance training — it does the amortization math for them and translates the result into "this is normal" or "this is worth disputing," rather than handing back raw numbers they have to interpret themselves.
Why it could be profitable
The free tier is a limiter, not a loss leader forever: one full deal check and a generic dispute letter, no sign-up required. A $9 one-time unlock adds state-specific legal citations and a PDF export, which matters to someone who wants a paper trail, not a repeat customer — most people buy one car at a time. The more durable revenue path is referral fees from consumer-protection attorneys who already work payment-packing cases on contingency; firms like Ginsburg Law Group are writing about this exact fraud pattern right now, which means there's a buyer for qualified leads on the other end of a "send to an attorney" button.
The timing argument is concrete, not speculative. California's Combating Auto Retail Scams Act (SB 766) took effect October 1, 2026, requiring all-in advertised pricing and giving buyers of used cars under $50,000 a three-day right to cancel. It exists because the federal CARS Rule — the FTC's attempt at the same protection — was vacated by a court in January 2025, so most of the country has no equivalent safeguard. Enforcement is also visibly uneven: on October 5, 2026, the FTC dropped its two-year payment-packing case against three Asbury-owned Texas dealerships rather than fight a constitutional challenge, even though the agency's own complaint cited a survey where 75% of those dealerships' buyers said they were charged for add-ons they never authorized. A patchwork law plus an agency backing off enforcement is exactly the gap a self-service tool can fill — I just can't point to a number of people who'd actually pay for it yet, that part is a bet.
Form factor & scope
A single-page web calculator — no login, no stored data, everything computed client-side in the browser. This prototype demonstrates the full core loop: enter or load a sample deal, get the payment-gap math, see which add-ons match known packing patterns, check California-specific eligibility, and generate a dispute letter.
How to run it
- Open
index.htmlin any modern browser. - Click one of the three "Load sample deal" buttons to populate the form with a real-looking deal, or enter your own numbers.
- Add any dealer add-ons by name and price, then click "Check my deal" to see the payment-gap calculation, add-on flags, and the generated letter.
What's in this prototype
- A loan calculator that derives the expected monthly payment from financed amount, APR, and term, and compares it to the dealer's quoted payment
- An add-on checker that matches entered line items against a reference list of 15 commonly disputed add-ons (GAP insurance, paint protection, VIN etching, and similar), each with a plain-language note on why it draws scrutiny
- A California panel that checks all-in pricing disclosure and 3-day/400-mile cancellation eligibility, including an estimated restocking fee if you'd cancel
- A dispute letter generator that fills in your numbers, cites the relevant rule (CARS Act for California buyers, the FTC complaint process for everyone else), and is ready to copy
- Three loaded sample deals (clean, mildly packed, and a California used-car case) so the flow is visible without typing anything in
Roadmap
- VIN-based lookup to pull manufacturer invoice pricing and flag inflated "market adjustment" markups automatically
- Expand the add-on reference list and CARS-Act-style rule set state by state as other states pass similar laws
- A saved-deal history so a buyer negotiating over several visits can compare offers
- The attorney-referral flow, with a real intake form instead of a placeholder button
- PDF export for the dispute letter and deal summary
Sources
- California's CARS Act (SB 766) Is Official: What Auto Dealers Must Know Before October 2026 — all-in pricing, add-on disclosure, and record-retention requirements
- California's CARS Act Takes Effect October 1: A 3-Day Right to Return Used Cars — 3-day/400-mile cancellation terms, restocking fee ranges, and the federal CARS Rule vacatur
- FTC Drops Its "Payment Packing" Case Against Three Texas Car Dealerships — the 75% buyer-complaint figure and the FTC's reason for dropping the case
Requirements
PackCheck — Requirements
Goals
- Let a car buyer check whether their financed payment matches what the loan terms actually require.
- Surface known payment-packing patterns in a buyer's add-on list without requiring finance knowledge.
- Apply California's CARS Act rules (all-in pricing, 3-day cancellation) to a buyer's deal when relevant.
- Produce a dispute letter the buyer can send without drafting it themselves.
Primary user
A person who has recently financed a car, or is mid-negotiation, and wants a second opinion on the numbers before or after signing. They are not expected to know what APR amortization means — the tool should translate the math into a verdict they can act on.
Functional requirements
- FR1: The user can enter amount financed, APR, loan term (months), down payment, and the dealer's quoted monthly payment.
- FR2: The app computes the expected monthly payment from the loan terms using the standard amortization formula and displays it next to the dealer's quoted payment.
- FR3: If the quoted payment exceeds the computed payment by more than a configured threshold, the app flags a likely payment-packing gap and shows the dollar difference per month and over the full loan term.
- FR4: The user can add any number of dealer add-on line items (name and price).
- FR5: Each entered add-on is matched against a reference list of commonly disputed add-ons and, on a match, displays that item's dispute note.
- FR6: The user can select their state and whether the vehicle is new or used.
- FR7: When the state is California, the app displays the all-in pricing requirement and asks whether the advertised price included all mandatory fees.
- FR8: When the state is California, the vehicle is used, and the price is $50,000 or less, the app calculates 3-day/400-mile cancellation eligibility and an estimated restocking fee.
- FR9: The app generates a dispute letter pre-filled with the buyer's deal numbers, the flagged issues, and the relevant citation (CARS Act for California, FTC complaint process otherwise).
- FR10: The user can copy the generated letter to the clipboard with one click.
- FR11: The user can load any of three sample deals to see the full flow without entering their own numbers.
- FR12: All add-on and sample-deal reference data loads from
sample-data.jsonat page load. - FR13: Input validation prevents negative numbers and a zero-month term from breaking the calculation.
User stories
- As a car buyer, I want to enter my loan terms and see the payment the math actually supports, so that I know if I'm being charged for something undisclosed.
- As a car buyer, I want to list the add-ons from my contract and see which ones are commonly disputed, so that I know which line items are worth questioning.
- As a California buyer, I want to know if I still qualify to cancel within three days, so that I can act before that window closes.
- As a car buyer, I want a dispute letter with my numbers already in it, so that I don't have to figure out what to say or cite.
- As a first-time user, I want to load a sample deal, so that I can see what the tool does before trying it with my own numbers.
Non-functional requirements
- Runs fully client-side; no deal data is transmitted anywhere or persisted between sessions.
- Works from a
file://path with no local server required. - Readable on a phone screen down to 360px wide.
- No external API keys or paid services required to run the demo.
Out of scope (for the prototype)
- VIN decoding or live manufacturer invoice-price lookups.
- State rule sets beyond California (the prototype shows how a state-specific panel would work, not a 50-state rule engine).
- Actually sending the dispute letter or connecting to a real attorney-referral network.
- Saving deals across sessions or across devices.
Open questions
- Where should the payment-packing flag threshold sit so it catches real packing without flagging normal rounding or dealer-fee differences?
- Would buyers trust a generated dispute letter enough to send it as-is, or does it need an attorney review step before the paid tier is credible?
- Is the attorney-referral fee model viable at the volume one person's single car purchase implies, or does it need a B2B angle (e.g., selling the tool to credit unions as a member benefit) to pencil out?
