On top of everything said: Throw the advertisement out!! It looks like the most unprofessional money grab. The whole page looks like it has been done in five minutes just to quickly grab some money off of it, the texts, the advertisement, the non existent design.

Also, it looks like this is all manually done, at least judging by the links. If you want any amount of turn over, both from devs and buyers, you need to get this stuff automated. Make it fast and easy to both buy and sell stuff, and toss away these ridiculous licensing terms!

To sum it up in one sentence: Try to not make it look like your first website made in an afternoon.