2 years ago I paid what amounts to $12.50/sq' to have my boat surveyed (buyers survey) out of Michigan, but it really depends on the area and demand. Also, I noted that the survey on another boat 6 months earlier (late winter) was a bit higher - don't know whether that was the time of year, or just variation. It is worth it to get a good survey. Good luck with the new boat purchase.
per square foot? that's new.