part time kegger question

Hello All!
Sorry to bother everyone if this question has been asked before... I have been brewing for a little while and exclusively bottling my beer. I live in a college town and beer is a kind of currency so I like the ease of trading six/12 packs for stuff, but for throwing parties, bottles have been a real mess - they get broken, I loose church-keys, and my bassett hound is constantly turning up bottle caps to eat even weeks later. So I want to keg the occaisional batch for parties. I got pair of cornies from a guy for $30 and want to know what the cheapest solution would be for carbonating and serving the brew... Whats the smallest/cheapest C02 cylinder I can use? The "Big Gasser" (http://www.schwedhelm.net/brew/biggasser.html) seems like a great solution for serving, but can I use it for carbonating also? Thanks for the info...

That looks like a superb system for serving.

Why not prime with sugar at kegg time and they will carb themselves. That way you have a cask conditioned real ale for the price of a cup or so of sugar.
That's the way I do it and at present am using a similar system but with out a reg.