I was having trouble doing so recently. The problem is that the site layout is very nonintuitive and stupid. The split in the departments in my opinion is not needed. For buildings you have to go to 3D Models/Architecture and for Vehicles 3D Models/ Transportation. After you have reached said locations you have to do a lot of scrolling in order to find what you need. It looks like they have fixed the issue I was having last week with the dead links. The sites a mess and I hope they redo the entire thing soon.

I posted links to each section for you to checkout

I can find my way around the site, does that mean I like it? hell no! Its ugly, everything is way too big, its not user friendly, has a lot of bugs and the staff is just terrible. I know I can be hard on things and people but. Should I really have to go through such a hard time to buy something. 

I found two new sites that have a lot of interesting content and a very simple web layout. So I am working on phasing out this store completely.

http://www.renderosity.com/mod/bcs/?TopID=359562.359698

http://www.renderosity.com/mod/bcs/?TopID=359562.359566