well...what are you into?
or better, what do you want to make / own?
I think it's senseless to say "you can make this and that", and it could happen that you don't like the movie the prop is taken from, or don't even know it.
the other thing, especially as you want it to be cheap, is: what are your...hmm, how can i say it. circumstances? do you have tools, do you have enough space to build and store your props (depending on how big they are/ will be), and what about material? for example, do you have access to scrap wood or something, or would you have to buy everything?
IMHO, you cant just ask "what can/should i build?". you should think about "what do i WANT to build?", and then think about how to do this