Be careful what you buy.
Although it's probably not what you want to hear, consider saving up for either Technics or Vestax.
I haven't tried many of the cheaper brands (or their cheaper models at least), but here's how it went with me...
As a teenager (too long ago), I bought a pair of Citronics (UK make?) plinths. These were the turntable platform but not mounted in an actual full turntable unit. These were then lovingly mounted into a homemade, dual turntable unit (a crude wooden box about 6 feet by 2 and a half feet, leaving room for a basic two channel DJ mixer in the centre between the decks). These did me proud, despite being belt drive and a little small (a 12 inch would slightly overhang the edge of the turntable itself). I certainly got a shit load of use out of them.
Later, when I could afford a pair of Technics SL1210s, I attempted, while setting them up to stop them (without slipmats) and was shocked when they nearly ripped my fingers off (in comparison to the Citronics).
I used the Technics for DJing in a pub for a while, along with my dual CD/mixer combo. These were stored at the pub as I didn't have transport available. This sucked big time, as I would have to listen to newly bought records in the pub through headphones before officially starting work.
To remedy this I bought a pair of Gemini XL500s (I think that's what they were called). The idea was that at least I would be able to preview tunes at home and decide on their appropriateness for playing out (there is a big difference between what I would like to play and what the public want to hear, sadly).
They were bad. The big problem was that the motor had no power to it whatsoever. This would affect both beat mixing and/or scratching (not that scratching was appropriate in the pub anyway). You adjust the pitch on one of the decks to match it with the one currently playing and it would take a second or two to catch up. Similarly, with scratching, you would have to give an artificial and entirely inaccurate push at the end of scratching to try and keep the rhythms somewhat together. Don't even try to adjust the tempo slightly by touching your finger to a record, and slow it down enough to fit back in, without the speed difference being audible to the punters. That shit would just stop dead.
Practical Advice:
The way you're talking, I'm guessing these are your first decks, and with that I guess you don't need anything too spectacular. However,
Try before you buy. Take one of your own records along. Find the first sound at the beginning. Pull the record back one quarter turn, and let it go. It better be going full speed when the music starts or the decks need to be damn cheap. I wouldn't buy off Ebay unless you are familiar with the actual model you are getting. Do some research. Try the actual model on Ebay in a shop but leave without making the purchase.
Don't sweat so much about belt drive versus direct drive. My belt drive decks shat on the direct drive Geminis.
Erm. good luck anyway.
Whatever you end up with, it's a really fun bedroom hobby, and can also be really satisfying when things go well publicly.
Post a mix on GAF when you get the hang of it.