Colt Thompsons have always seemed to be the most volatile of all transferable machine guns in terms of prices paid since the end price (as many of the members here know) is dependent on several factors rather than just being on the NFA registry. It is almost sacrilege to place a value on one since they are by far and away the most iconic and classiest American firearm in history. That being said, you will get what you pay for. There were three that I saw at the previous SAR show here in Phoenix and none were listed for less than $34,000. If you want one now, you will pay a liberal premium for that luxury ie. $45,000 to $55,000. Through the generosity of one the board members here, I ended up committing to a Colt Thompson in the mid 20's range just over a year ago when three years ago I was planning on saving my money for a Westie. From what I understand, Frank's guns is still brokering that Navy 21/28 that popped up on GunBroker a few months back which, from what I am told, is in rough condition and does not have matching upper and lower and has WWII parts. It might be worth reaching out to the original owner even though they wanted an arm and a leg for it at the time. There is no reason the original owner can't be negotiated down, especially if he wants to get rid of it. Might be worth looking into as a shooter and with the right bluing service, can be restored to it's beautiful original factory blue. Best of luck in your search.