3-rotor Enigma machine being auctioned by Christie's London

For a personal collection and actual use, rather than spending $80-150k for a German wartime Enigma, I'd probably be more likely to buy a Swiss model.

The Swiss NEMA is basically an updated version of the Enigma, and is about $3-5k. http://en.wikipedia.org/wiki/NEMA_(machine) -- plus they were not actually used except for training, so they should be in much better mechanical condition.

(I'd still love to own a 4-rotor naval enigma myself someday, but they're rare enough that even if $100k weren't significant to me, I would still feel it should be treated as a rare historical artifact and not used)