Good gaming mouse that isn't too expensive?

I've used A4Tech Oscar X747 for the last few years and I'm ever so satisfied with it. It has 2 convenient side buttons, one not-so-convenient (my finger is too short) button at the the very end of the main button and the DPI change button. However, you are free to reprogram all of the buttons for your liking (it comes with an editor, you can write scripts in or just use pre-made one). It also has a sensor that stops the mouse when you lift it (if you're that kind of a player) and some counterweight inside that you can remove or change (there are 8 or so little counterweights, you can use as many as you want). The cable is really stiff and solid.
I've bought it for less than 20€ (70PLN).

A4Tech X-718 it's cheap, simple and reliable but with enough bells and whistles to feel great.
Guys, he said not expensive, you're running around here recommending him Deathadder and Rival ffs :P. They are overpriced, not worth the trouble.

And... he's Suspended now. :T

Look around for Corsair gaming mouses, they are really great

Ended up going with the Logitech G502 when it was 20 dollars off. Just seemed right for me. Thank you all for the suggestions though. <3

I would 100% recommend Enhance GX-M1. It's a 3500 dpi gaming mouse and requires no drivers at all. It just works and you can toggle the dpi with a switch along with multiple colors or turn that off completely. I've bought 2 for myself and 3 of my friends own it. It's also a steal at $19.99 in the U.S. I bought mine for even less and I've had it for quite a while.

edit: Sorry I missed your message about buying one already. Hope it works good for you :)

Microsoft Intellimouse.

Apparently it's cheap, tracks excellently, has two thumb buttons, and can be overclocked.

I use a Deltaco gaming mouse. It cost me 4 euro. I have a tendency to break the mice easily, but this one has lasted four months, so I am happy with it. Most other mice I have tried ended up double-clicking on each click or the scroll wheel would dislodge.