Hah, so this is what it is:
That size(same as in my office) fits 3 1/6 bbls(pony kegs..a 1/6 barrel is 5.12 gallons of beer). You can get one pre-built for about $350. Each keg has 40 pints. Most 1/6 bbls are about 70 bucks...so a little less than 2 bucks a pint. You need a Co2 tank and regulator go with it. Air hose and tavern head(coupler) will be included. Best way to do it in my opinion.
If you buy a cheap domestic...like Rolling rock, a 1/6 will cost you about $45.
You can also get one that holds a 1/2 bbl of beer....15.5 gallons or 50 liter (13.2 gallons). 124 pints out of the 1/2 bbl, 100 out of the 50 liter. A 1/2 bbl of rolling rock will run you about $90. Now you're less than a buck a pint. Not quite the 2 gallons for 10, but close.