Excellent-condition f/2.8 Summarons are going for $900 - $1150 on *-bay.
Sounds like you have a good buy if the 'cron is in good shape (consider having the salesman take some test shots at the near focusing range to rule out back-focus issues with the goggles. If he's had it in stock that long he shouldn't mind [with you paying for the film & development, of course]).