Focal length unimportant. scratched, dented, dead aperture ring all fine…you get the picture….
but must be cheap :) or swap for something, say, film. I guess could just buy a Jupiter-8 from Russia for 12 € plus shipping, but i dont need the glass even.
I take it you’re looking for just the mount, for some sort of interesting project :)
Large 2nd hand dealers might be an avenue to try. I’ve seen mwclassic.com sell lenses very cheap (~£5) for spare/ repair on occasion, where the glass was beyond salvage. I’m sure if you emailed them, they might keep an eye out for one for you,