Thanks a lot. Anything else I should look for when going to see?Ebay?
Look, as a guy who rebuilds used spas I can tell you that if you see it hot and running and not leaking everywhere you're likely good. But go look at it, don't buy unseen.
There will be extras. Covers are usually in pretty bad shape, cabinets need refinishing or repair, pumps leak a little, etc. But to get something decent in your budget used is about your only option.
Caldera is made by watkins, who also make hot springs, and is a top tier manufacturer, but parts are expensive.