Hiya Jerry,
I think for one, you'd wanna make sure the motor didn't sound like it was going to fly apart.
When you crank it up, you want the blade to spin nicely without any wobble. Might want to take a new one of your own to put on it in case the one on it is bent.
Look for the adjustment bolts where the motor mounts to the frame. Make sure they aren't welded on with rust.
A belt is an easy replace, so I don't know if I'd worry too much about that.
Confirm that the pump works.
Look for signs that it has been dropped or the frame has been forcefully bent.
I haven't priced out saws lately, so I'm not real sure if that's a good price or not.
Hope that helps a little!
