Shooting b&w film. Testing with Ultrafine 100. Budget for lens would be as you say $100 ish range. Anywhere from a 135-180mm even if I am incredibly lucky a 210. The shipping will be the deciding factor.
Measurements on lens board 1.5" or 39 mm. also needing some film holders. (Lisco Regal II) The one he "gave" me has a damaged dark slide.