Trials is great for cheap riding. The bikes just don't wear out like MXers... its many years between top ends for most people.
Yes. If it's the Kroo with the radiators in the "gas tank", this bike is known for being a bit tall for a trials bike. Also the 250cc version of the Kroo (the most common in the US) was pretty fierce for a trials bike.
It's a great bike for larger riders, and for riding on the loop.
OTOH the 212cc Fantics of that era were quite softly tuned, great for smaller beginners in sections.
This is a 250cc KRoo:
http://www.msnusers.com/mgo4/shoebox.msnw?
action=ShowPhoto&PhotoID=28
The Trials shop (trialsshop.com) has parts.
The guy who was Fantic importer in the US retired, which is too bad 'cause he's really nice.
I think the trials shop picked up all his inventory.
I'd recommend a bike with disc brakes and water cooling, unless you are going to go all the way back to vintage (pre 1980 in the US).
Discs work a lot better and water cooling means no overheating while practicing.