I didn't know you were a moderator LL.
I might be missing something, but I can't imagine someone wanting to invest in stage magic without the plan/idea of eventually doing some kind of show. With that said I would definitly suggest spending sometime checking out some established professional magicians to see what kind of stage magic you like best (comedy, dramatic, big illusions, or some kind of combo). One inexpensive way you can start doing that is check out some of their web-sites; a lot of them have clips from their shows(here's 2: Tony Clark(doves and pretty things), Tony Albano(funny yet magical)). I believe that doing something like that will save you a lot of money in the long run. I know I have a lot of props that I spent good money on that just don't fit my character or my show. The most expensive prop that I use in my 1hr. comedy magic stage show is a $40 vanishing ketchup bottle.
I guess the other bit of advice I would give is to try to invest in performance videos to find stuff that you like, and to see how the pros do it.
I hope this is helpful; its just the conclusion I have come to after $100's of dollars spent, but it is going to make a good chapter in my book one day ("What you wish you knew before you spent all your birthday money on 2 earth magnets")
where did you get the vanishing ketchup bottle for $40. every where I have looked it has been over $50