Beginner Build Ideas

I'm new to prop building although I've wanted to do it for some time. I've got a long list of things that I would like to try, but I'm currently short on funds (one kid in college and one teenager at home). I've recently seen a couple of things that I think can be built cheaply, but thought I would throw it out to this community for ideas of things I might not have thought about. What are some cheap and low skill level builds that I could get my feet wet with? I'm not too experienced with soldering, so the arc reactor is a little intimidating (although I'd love to get the kit I've seen and try it out). I'm hoping to start on the psychic paper holder I saw yesterday. I've wanted to build a lightsaber (big yellow box is helping with this) and eventually (not anytime soon) I want to get up to a K9 and R2D2 units.

As I said, I'm just beginning, but I have most basic tools (including a dremel tool and soldering gun). I have access to scrap sheets of polystyrene and pvc (perk of working at a sign company).

Thanks in advance for the help!