If I wanted to start my own server

to run off your home computer take a look at this, skip down the page a bit and I list the different methods of going about that
http://forums.tf2maps.net/showthread.php?t=4001
just be aware that running a 16 slot off your home server is highly unlikely to work well, unless you have both a very good internet connection and a good computer

if you want to rent there are a few methods you can use, these are the companies ive dealt with:

http://magnirack.com/ If you don't mind a server in texas I strongly recommend them, servers are stable, cheaper then gameservers, some of the best support ive seen and if you contact support about discount coupons the price can be further dropped

http://www.gameservers.com/ Sort of the standard for game servers, in my experience their servers are...kinda stable, and the support is so-so, but they have a wide selection of games and locations. They cost the most out of the three.

http://www.discountgameservers.com/ Their cheap, have stable servers, and have a few locations to choose from. On the downside they support a small volume of games, and their support...well...who are we kidding, their support is painful, even they admit it.

well...if your paying for it I don't really see how anyones input is important

generally speaking though...what they don't know doesn't hurt them

paypal is the way to go usually...and don't use the "im 15" excuse
i ordered a $2500 computer with paypal when I was 15 <_<

and a 3rd option came to my mind...there are a ridiculous amount of completely dead servers that would likely be willing to give your group a good amount of access, probably ftp, in exchange for populating the damn thing