Have been looking at Bullfrogs but this popped up, its a 2016
http://fredericksburg.craigslist.org/hsh/6263929296.html
Its a good deal if
1) you can see it running and heated, don't buy anything based on them telling you it worked fine before they drained/stopped using it,
2) it meets your general needs,
3) the price is right based on its age/condition but from that pic you can't tell if its 5 months old or 5 years old or ...
Also, since it says "We can deliver FREE to your house within 45 minutes" this sounds like a dealer (or someone who deals in used spas). You'll certainly pay more from a dealer than from an owner but you also get the peace of mind that they have checked it out and if its from a dealer you can negotiate a store warranty. They'll probably offer 60 or 90 days to you without asking but I'd shoot for 180.