Sabco charges $60 for the cleaned and cut keggle only, $100 for the keggle drilled with welded stainless couplings for bell valve and thermometer. Shipping to Kansas was an estimated $20. You can add on whatever you want from there: ball valves, false bottoms, thermometers, sight glasses... $200 would probably be about right for one with a stainless ball valve, ready to go.
I was strongly considering buying the $60 job and drilling it myself, jerrymandering my own bulkhead from brass fittings, brass ball valve, etc. What I bought just seemed like a slightly better deal. You can get all the brass fittings anywhere--stainless is a little harder to find non-mail-order