I'm not very familiar with Visio brand aquariums, but $60 for a 50gal tank is a fair price.. I would ask to see how long it had water in it and give it the old leak test.
I've had a visio 60 gallon tank as my main display for several years now with no complaints. That being said, i think i paid $80 for it new so it seems you aren't saving a ton of money by buying used. I am in socal though were prices tend to be more competitive that other places.