I just sold a really nice 1200, 48" deck, with a newly rebuilt engine, this spring for $650.
Something to watch out for is the motor mounts. The 1xxx series tractors were the first to have the engine bolted to a steel plate, which bolts to the frame through a set of rubber bushings, ISO mounts. This was part of the "Quietline" design, along with quieter mufflers and the engine side panel enclosures. All good measures, but they had their down falls. The gear drive models are known for wearing out the ISO mounts, letting the engine flop around, which in turn tears out the clutch disk. Not a big deal, but it is something to be aware of. You can tell pretty easy, open the hood and give the engine a shake. You'll know if they're worn out.
1951 Farmall Cub, Cub Cadets 102, 104, 1811, 1864, Simplicity Legacy XL 4x4 Diesel with FEL, 60" mower, 50" Tiller