Either a C or Super C.$600 I think is a pretty good price.
If it was running a year and a half ago and it's been shedded the last 3, it may not be stuck. Reach in and give the fan a spin by hand to see if the belt will turn the main pulley.
Good pictures. Looks like there's another tractor sitting in the shed right behind it - what is that one?
I know where there's an all original running H (still 6 volt) that's been kept in all it's life and the guy only wants $1000 for it (but I'm not telling where. ;o) )
Hopefully one of these days I can build a shed to put it in and buy it from him before he tries to actively sell it.