The semi thompson prices are all over the place depending on who made them and if they have the removable buttstock. When I was looking for a 1927 a couple years ago the low end was in the $700-$750 range for a vg/exc condition one, and average was about $800-$850. I ended up getting a new Khar made one with the removable stock for $1100. Check gunbroker to see what they're going for now.