Parkertrailers,
These are tough little machines, but it is difficult to say without the correct # of hours and the year. IF the tractor has four lug nuts on the front wheels, then it is a late '70's-early '80's tractor. If it has 6 lugs, then it is probably a 1990's model. If the machine has a hydrostatic tranny (essentially an automatic), it is worth more than if it has a standard tranny. Does it come with anything else besides the loader? Depending on the shape it is in, how strong the clutch feels, how well it runs (does it still put out a lot of blue smoke once it is warmed up?), and what region of the country you are in (in the northeast these little machines are hard to find with a loader!), I would ball-park it in the $5,000 range, give or take a little. I know some of this was pretty vague, but without specific info. it is hard to say. Finally, sometimes if you give the serial number, some guys on this site will tell you what model year it is. Good luck whatever you decide.
Teach