oh my...
From that photo, it looks to be nice, cant even see any surface rust on the cart. Ask them if they use it much, if not, maybe they don't care to much about it? Maybe even offer to buy them a new OTG or OTS to trade? You never know. But as the others said, bring extra money with you. Cash is always king. If its in that nice of condition...bring fresh 100's with you. It will be sure to get their attention if they might be on the fence! Keep us posted.