The rig I'm on right now started out as a bare bones system from TigerDirect.ca
It came with the following:
Motherboard - Asus M2N68-AM SE2 µATX Motherboard
Processor - 2.60GHz AMD Athlon II X4 620 Quad Core with heatsink and fan.
Ram - 1024MB Ultra PC5400 DDR2 667MHz Memory
Hard Drive - 250 Gig WesternDigital IDE Drive
Power Up Black ATX Mid Tower with Extreme ATX 450 Watt power supply.
It was a less than 300 Canadian including shipping and taxes.
I've since added a GT 220 PCIe video card, another 2 gigs of ram, and swapped out the IDE drive for a SATA 2 hard drive. Windows 7 Home Premium x64. I have no complaints, it does what I want and plays the games I like. I didn't have a lot of money to spend on a PC and wanted something that I could pretty well use right away. I'm a retired electronic technician so the some assembly required part wasn't a problem for me.