They are pretty hard to come by. Anybody who owns one is probably holding it close cause you can't replace them. Keep an eye on Ebay, sometimes they have repro kits and originals that show up for a good price. Also if you are coming East for any of the Gettysburg events, there is an antique store that has cases of period medical instruments. For the price you would pay for an Archer kit you could get a good set of original equipment and case.
your obedient servant,
Surgeon, 2nd Brigade
"not really a surgeon, but I did stay at a Holiday Inn Express"