sankey ball tap is your best bet for common beers (anheiser busch, coors)
prong tap for ginsee ale and some imports
if one was so inclined to do a ghetto riggin, get the tap and the spiggot from the distributor. co2 tank, well, look around, there is bound to be one that fell out of the back of a 7-11 somewhere. pressure regulator, if someone has an oxygen acetyline torch laying around that can be parted..... make sure you grab the oxygen regulator, it has right hand threads that mate to most common co2 tanks. the acytelyne regulator has left hand threads
about 4-7 psi on the output of the regulator for most beers, depending on the length of line the beer has to travel, and its tendancy to foam.