Seth Godwin’s apps

Used Car Sale Aggregator

Aggregate used-car listings from multiple marketplaces with search, filters, and price comparison.

One search across the marketplaces people actually list cars on, so a buyer stops running the same query in five tabs. Every listing is normalised to the same fields, priced against the market, and deduplicated when the same car appears twice.

What a v1 does5 features
  • One search across dealer feeds and the major marketplaces
  • The same car recognised across sites and shown once
  • Each listing scored against comparable sales - over, under or about right
  • Saved searches with alerts when something matching appears
  • Filters for the things that decide it: mileage, owners, accident history, title

The market

Adjacent marketCar buying and resale
$20.3Ba year at Carvana, which sold 596,641 cars in 2025

CarGurus takes around $232M a quarter from its marketplace, mostly from dealers, and draws 30 to 35 million monthly visitors. Carvana earns on the cars it sells. Neither charges shoppers to use it, so a $6 a month consumer subscription would be a different model to anything proven here.

Where these numbers come from
CompanyEarnsReachSource
Carvana$20.3B revenue, 2025 (+49%)596,641 retail units sold, 2025Public filings
CarGurus~$232M marketplace revenue, Q3 2025 (+14%)~30–35M monthly unique visitorsPublic filings
Cars.comPublic marketplace compNot publishedModel, not a disclosed figure

Why this audience

These viewers know that the deal is found rather than negotiated, and that means looking at more listings than a person reasonably can. Search across every marketplace with prices scored against the market is the mechanical version of the advice they already follow.

Before it can launch

  • Listing data through marketplace APIs and dealer feeds rather than scraping

What it earns

Drag me Every figure recalculates as you go.

Paying users1,000

0.056% of 1.8M followers · capped at 50,000

Price per month$6

Opens on the price this idea was costed at, $6.

1,000 paying — 0.056% of 1.8M followers — × $6 a month = $6,000 a month

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Revenue a month$0123456789,012345678901234567890123456789
Over twelve months$01234567890123456789,012345678901234567890123456789

Fifty thousand paying users is the ceiling every one of these pages is drawn against, not a forecast. It opens at a thousand, the bottom of the range, so the first figures you see are the modest ones. What the cap buys is comparability: the same range on every app, and the percentage of the audience it takes as the number that moves.

Is this the one for your audience?

We fund it, build it, and run it. You bring the audience and take a share of the revenue. Nothing to pay and nothing to build.

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