I've several friends who have purchased used "regular" hot tubs for less than this. Garage sales in both cases. One guy got a fully functioning 10 man hot tub for $100. I had the misfortune of helping him put the thing on his truck . I guess a lot of people buy them (around here) and then don't want to bother maintaining them.

Honestly, even though I've got a spa attached to my pool I have occasionally considered getting an above ground tub. The bubble action isn't as good on the in-ground and I can't keep it heated all the time so it's an hour of prep to get it ready for use.