Cardboard — design concept

Trade, made real

Today, tapping “Trade” just relabels a cash sale — no value on the other side, no incoming card, no cash math. These two screens sketch what it looks like when Trade actually knows it's a trade. Nothing here is wired up yet.

The one rule that makes this honest: the card you receive books its cost at what you truly gave up — your card's value plus any cash, never the incoming card's own appraisal. Fair trades make the two agree. Lopsided ones don't — and the app should say so, not hide it.

Screen 1 · Regular sell flow

Trade-in, one card

MarkSoldScreen today: pick a channel, type a price, done. With Trade selected, the price input gives way to what's coming back the other way — scanned in through the same pipeline every card add already uses.

2021 Prizm Ja Morant Silver #83
Cost $40.00
Sold for
$100
Cash Venmo Card reader eBay Trade
Cash only Card(s) + cash
2023 Bowman Chrome Wembanyama Auto /499
Scanned just now
Comp $200 · tap to edit
$200
Scan another Add manually
You pay $100 cash
Their card $200 − your card $100 = $100
Editable — this is a suggestion, not a lock
Profit on this card +$60
New card's cost basis $200what it'll show as "paid"
Screen 2 · POS cart (dealer / show)

Trade at the table, N-for-M

The cart already handles multiple cards and a haggled bundle total. Trade adds a second list for what's coming back, and the gap between the two totals becomes the cash line — editable exactly like any bundle total today.

2019 Chronicles Ja Morant RC
Panini · #201
$30
2020 Prizm Silver Luka Dončić
Panini · #79
$70
2023 Prizm Wembanyama Silver #136
Scanned just now
Comp $200 · tap to edit
$200
Scan card
Cash Venmo Card reader Trade
Your side
$100
Their side
$200
Gap $100 cash to them
$200 their side − $100 your side = $100
Profit on this sale +$60on the 2 cards sold
Concept only — colors, copy, and layout are open for reaction. Purple marks anything trade-specific so it never reads as an ordinary cash sale.