ebay/craigslist might have some $ info on such.

M/W, here's a neat video on a similar machine:

Here is a link that might be useful: GTH 16

Hey Smatloff,

I have a '93 GTH16 with a 50" deck and a 42" blower. I mow about 4 acres every other week and clear a 300' driveway when necessary in winter. I bought it about 5 years ago for $750 with 650 hours on the meter. It now is rounding 1,000 hours and still going strong. I've had to replace the PTO and the battery but otherwise it has just been regular maintenance with belts, filters, oil, etc. The BS Vanguard engine has to be one of the best I've seen (knock on wood). Hope this helps and good luck.