Well, unlike computer equipment, most DJ'ing equipment isn't really upgradable. What I would recommed it buying some low-end direct drive tables, and a decent mixer that has a few features/effects that you can play around with. That way you wont have to invest as much money up front, but you can still learn to beatmatch on direct drive tables and learn a few mixer tricks. I don't think any equipment is going to "hold you back" because if you land a gig somewhere, most likely you wont be taking your own equipment with you.
What I would probably suggest is picking up a "turntable package" that includes tables, mixer, cartridges, slipmats, headphones (and some even contain small crappy monitors) and mess around with that for awhile. Then if you decide to "upgrade" you can buy new tables, mixer, headphones, etc and swap them out later on. This way you only have to drop a few hundred dollars up front.
PlanetDJ.com sells quite a few turntable packages and their prices aren't too bad. The best thing about their site is that they ship any order over $250 for free, so buying this sort of heavy equipment from them saves you quite a bit in shipping costs. I've ordered a few things from them before and never had a problem.