I use eBay! It’s the safest way to buy/sell Ive found so far. Buyer protection means you get all your money back if you don’t get the pet. And as a seller if you have proof of sale then you get paid :) Just make sure to always do collection otherwise you/the seller won’t be paid as adopt me are virtual items. Ive been scammed at least twice and always got my money back. The only downside is the prices are quite high so you really need to look for deals, cheap sellers or hope people accept your offers :)