HELP: Apple III

[sydtech@skypoint.com (Scott Butler)]

I collect classic systems, and just picked up an Apple III with monitor 
for $10 from a thrift shop. Not surprisingly, it doesn't work. I switch 
it on, and get some interesting random garbage on the monitor.

The questions: I recall that these things had an obscenely high failure 
rate. What was the problem in most cases? Also, what kind of OS do I 
need for this thing? Is it Apple II compatible?

Sorry to post here if it's inappropriate; it was the closest thing I 
could find....

Thanks!
Scott