Hey, good questions.

1) We make money primarily through sellers promoting their listings, similar to eBay listings. For a fee between $.5 and $10, sellers can promote their listings in various ways.
In addition, we are due to implement a 2% fee for transactions paid in cryptocurrency to be announced next week, but 0% fees will remain for both PayPal and Stripe.

2) PayPal and Stripe payments are sent peer-to-peer, we don't custody the payment itself. It's not as risky as you think, since we provide the seller with more than enough evidence which can be shown to PayPal in case of a dispute.

3) We do indeed have a steady stream of interested buyers visiting our platform, so our primary focus is to recruit more sellers.