Condition is everything and gas usually means problems. Its probably a dual range 4 speed giving you 8 forward and 2 reverse (hi-lo gear shifter). Depending on condition I wouldn't buy a gas tractor but if you insist, wouldn't give more than $4k for one in really good shape, new rubber and properly serviced over the years. I recently bought a 3600 diesel with power steering and remotes on the rear, new rubber, nice paint, newer seat, had a few things to replace not costing more than $300 total. I gave $6k for it and having fixed the little problems have a really nice, rugged tractor. Would not even consider buying a gasser.