Happiness is a Cold Homebrew

So I’ve begun thinking about kegging my beers. It’s become something of a necessity these days, mainly due to the fact that I am sick and tired of bottling each and every batch of my beer. Since beginning my all-grain brewing odyssey earlier this fall, the amount of beer leaving my brew kettle has steadily increased, and I am running out of space and bottles. Therefore, I think it’s time to begin kegging my brews, both for simplicity and as a way to better serve my brews to others.

But I have some questions, because my experience is somewhat limited with this particular method of storing/carbonating my finished beer.  

1) Do I need to have a refridgerator to chill the beer in order to force carbonate it, or can I carbonate the beer at room temperature?

2) What kind of money am I going to be spending on this whole setup? I know I’ll need the keg(s), a CO2 canister and all the lines needed to hook everything up, but I’m wondering how much it’s going to cost me.

3) Are there any disadvantages of kegging a beer vs. bottling it? If, for example, I brewed a big, beastly Imperial Stout and decided to keg it after aging in secondary, will the beer continue to age and mellow out in the keg, or is that something better left to bottling?

Well there we go, some food for thought for all those out there with more experience than myself. Hopefully I’ll get some good feedback, I usually do. Thanks very much in advance for the help, and Happy Brewday!