I look at general wear and tear, avoid anything that has been bent or welded. Leaking hoses arent too bad, leaking cylinders could get expensive quick. If these turn out to be truly vintage, take a good look at the pads, I prefer large pads, but some were available with tiny ones. Also look at the thickness of the arms, manufacturers did funny things way back when, so if you have a low vehicle to lift, extra thick arms might not cut it. If the auctioneer requires a rigger or somebody else who is insured to remove, skip it, otherwise dismantling and moving lifts is rather simple. If you dont think you can do it, you probably shouldnt be using one.
With auctions you have to realize that everything is either ridiculous or easily affordable. If its on a weekend, youre probably going to have to fight with every joe blow in the county, so try to attend some mid-week ones instead. Real auctioneers actually tend to schedule shop closings for the week to attract the serious buyers, beware the weekend shop sales = cheap thieving SOB auctioneers. Two posters either go for $500 or $1500 for nice units, depending upon the crowd and the size of the shop closed (bigger is better). If theyre junky, old, or well beaten on, they go as low as $100 quite often in the northeast. Unfortunately, you missed the big round of dealer closings two summers ago, those deals made me look overpriced.