If you want to keep the price down, stick to the mom and pop online shops. In other words, don't go to Dell, HP or Gateway.

I usually go to the mom and pop shops even for high end stuff since I like the case mods they do (neon lights, see through window) etc...

I'll give you 2 shops to take a look at. Both have been good and they have a nice configurator so you get what you want.

http://www.cyberpowersystems.com
http://www.ibuypower.com

Good luck and let me know if you need help with any tech lingo.