Looks like a very old model and cold have seen some abuse. Older models like that in 0-1 sell for no more then about 10-15 CAD on auction. I sold whole 0-4 set of a Starrett for like 70 plus fees.
Generally 0-1 are cheap anyways. If it works good offer 20. Maybe 25.
I sold I think 3-4 to Dabbler Kent and Moore for I think 35 - and it was in pristine condition. Plus it was 3-4 not 0-1.
Look at the adjustment handle - it I think shows rust or at least some contamination.