I'm considering getting one myself, but I figured I would share with users as well. If you're interested send me a message and I'll tell you where to go and find the info.

I know of someone selling a number of servers for a decent price. As an example here are specs on one of them

AMD MP 64 2400+
2GB of Ram
120GB HDD and 250GB HDD
Asking for: $100

The asking prices are cheap, nothing over $100 except for one but I believe it's sold. The servers are in 1U and 2U cases.

These servers are in a datacenter in Kansas City that offers colocation with the following specs

Single Server
up to 4U
1Amp of power
500GB of transfer
8 IP Addresses
(5 useable)
FREE setup
$50 / month

So for $50/month you're running your own server.

Colocation isn't for everyone. Remember that there's no hand holding with colocation. If a hard drive dies then you send them a new one and they charge you to replace it.

But it's a good way to begin if you're interested.