That sounds a little high to me. Especially if the loader is a trip bucket type, not all hydraulic. A box blade is nice, but they are less than $400 new so it really doesen't add that much. New front tires/tubes will probably set you back $100 so I would offer about $2800-$3200 and see if that is acceptable. If the loader is all hydraulic I would go up to $3500.
My two cents,