We sold a FarmPro Jinma 20hp without loader or 4wd last year. It brought $2000. We paid $3000 for it in 2005 (2003 model). They are cheap homeowner type machines (think big Sears lawn tractor for quality). They can do the job but are not for a person who takes a machine in for every creak and rattle to the shop (Buy a John Deere instead). These are low quality usually easy to repair and do break type of machines. With Chinese quality bolts that are 1/2 metric and 1/2 standard sized (think low quality bolts). They can do a homeowner job and work ok for that.
As for value I'd guess it'd be worth $5k in perfect stored inside condition (chinese rubber and hoses etc do crack badly). If it's not in great condition then think 1/2 of that IMO. Just remember, it's Chinese and will need maintained better than a better brand and quality.