There's a couple of swap and sale Facebook groups. Here's one: https://www.facebook.com/groups/254893731351993/ Some shops, such as Thick Bikes, also have some used bikes in stock. Be sure to check them out. Aside, do you want a fixed gear or a single speed? I understand the simplicity allure of the fixie, but going downhill on one sucks. Around here, I'd recommend a single speed, so that you at least can coast whenever you go downhill. If you do decide to go fixed, make sure the bike has brakes. Some people consider them redundant on a fixed gear bike, so don't be surprised if some of the fixies you find have no brakes. Also, in PA, you are legally required to have brakes on your bike.