OfferUp has some good deals but there are too many scams and the app developers don't seem to be removing them or implementing a system capable of removing them quickly. I would say that about 1 out of 20 ads are fake, but that in terms of the "good deals", 80% to 90% of the ads with a good price (below market) are fake. Another problem is the review system. If somebody scams you, all they have to do is not mark you as the buyer and they can avoid getting a one-star review! It's totally rigged.