If you have no experience with band saws I'd suggest if possible ask an experienced friend to go with you to look at, examine and test it.
Is the miter slot square to the band, is the band 90 deg. to left and right, front and back of the table, if not why?
Are adjustments to correct any of the above available on the model and relatively easy to get at, e.g., not rusted solid?
Are the tires round or are there flat spots?
Are the guide bearings lined up, if not why?
Does the machine make odd noises as it runs without cutting materials?
Does the guide post move up and down and lock smoothly?
If any of the above exists, all or most can be addressed with a little smarts, tools, labor, time and more money above the initial cost of the machine. what you need to do is decide if it's worth it or your money is better spent with a new machine and a warranty .
Never bite the hand that looks dirty!
The more you know the more you're worth