I don't have any experience with colocation, running from home or rent a certain amount of slots. I was lucky to get to know a guy who rented a root server or dedicated shell server. He ran everything on it, SQl, web, php, multiple game servers, Ventrilo, ftp ... Everything he ever needed was there, on the same box. This is ofc more expensive than renting one server, but if you would rent everything you can run on a ded server separatelly you would have to pay a LOT of money. So the total cost of each service you can run if you rent a ded server is very very low.
I don't know what this costs in USA but in Europe you can find shell server providers for 30-40 Euro/month which has:
* Dual core cpu's
* 2 GB ram
* 200 GB disc space
* 10 mbit up/100 mbit down
* Unlimited bandwitdh usage
It is more work for you initially as you have to set everything up yourself. But they come preinstalled with an OS of your choice + ip + Apache running + SQl + PHP.
There are tons of tutorials on the Internet how to go about doing this, so learning it shouldnt be any problem.
The problem is financing. Best thing would be to go together with 3-4 people who want to run their own servers and you pay together.
I know what I'm talking about as I have rented ded servers for 2 years and I am very very satisfied with it. The convenience and dynamic use of a ded server can't be compared to anything else. And having everything you need running on the same box will make your life really much more simple.
A quick search for USA show that you wont get a ded server under 70-80$/month which can handle your needs and do what I described here.
http://www.askwebhosting.com/dedicated-server/?SortBy=1