how much,,I wouldn't pay more than the lowest cost hard tail mtn bike on sale, whatever that is. The problem for me is that you really don't know the condition of the wheels, is the headset pitted, etc. A new set of bombproof wheels and headset will cost close to that much retail. What you are getting is a package and if the size of that package is what you want,,ie. is the frame really your size it would be worth bidding on. The front rack set up is kind of weird, it looks like a rear rack mounted on the front for a rear pannier set up. I'd put on low riders and not hang such big bags out in front.
Personally if it was me and I was looking for a deal I'd want to be able to ride the bike and check it's condition first hand. If money is that tight what is your recourse if you want to replace a headset or rear wheel because it has "auto-steer" or there's a wobble in the rear wheel with a few over tight and over loose spokes keeping it straight?