About Cardboard Terminal

A free deal finder for graded trading cards and sealed product, built by a collector who is also a data scientist and got tired of refreshing eBay.

What it does

Cardboard Terminal watches live eBay auctions and Buy It Nows for graded cards and sealed product, reads the grading label on each slab, prices every listing against recent recorded sales of the same card and grade, and shows the listings below market first. The deal finder is the live feed. The card price pages give every Pokémon card its own page with prices by grade, a price history and the copies for sale right now. The iPhone app adds push alerts for the cards, sets, grades and prices you choose.

Where the numbers come from

• Listings come from eBay, continuously, through eBay's own developer programme and the public listing pages.
• Prices are recorded sales of the same card and grade. The headline figure for a card is the median of its newest sales, and the number of sales behind it is always shown.
• Grades are read from the certification number on the slab and checked against the grading company's record, so a listing is priced as the card on its label, not as its title.
• Populations come from the grading companies' published reports.

In hobby terms, it is a live list of cards selling under comps on eBay, sports and Pokémon alike. Nothing is hand-curated and nothing is sponsored. A listing is in the feed because a program read its label and found comps, and it ranks where its price puts it.

How it makes money

Cardboard Terminal is a member of the eBay Partner Network. When you click through to eBay from the site or the app and buy something, eBay pays the site a small commission. You pay the same price either way. There are no subscriptions, no paid tiers and no sponsored placements in the feed.

Who builds it

One person, a collector and data scientist who posts as Prof. PokeQuant on X, with a lot of help from automation. The site launched in September 2026 and the iPhone app followed in October 2026.

What it is not

It does not sell cards, hold inventory, bid for you or give financial advice. Every bid and purchase happens on eBay in your own account. Recorded sales describe what has happened, not what will.

Contact

Email professor@cardboardterminal.app. Bug reports with a listing link and a screenshot get fixed fastest. The support page covers account and app questions.