You say 'getting greedy', and I say 'getting out of competition with credit/debit card thieves who can offer Amazon purchases for almost any discount and still profit with near-zero expenses'...
Let's call the whole thing off!
Do you know that for sure?
Do you know how purse can offer 20%? Are they stealing cards?
Its not actually purse that buys it, its basically a bitcoin exchange. You give them your btc, and for a fee (quite large) they buy your item.
Its very fast if you want btc, put up your offer and you can get btc within minutes, but bank wires and transfers can take days.
But 20% is quite big for buying btc, even for how fast it is.
There might be an additional discount, so it closes the percentage to maybe 5% fees the buyer pays.