I am no expert, but I just ordered a used HandyBoard for USD $100 (bargain),
and it can use the freeware Interactive C (an interpreter I think, rather
than a compiler). There is heaps of example code out there on the 'net.
A commercial version is available for only USD$35:
A freeware version of the early Imagecraft compiler (and a free IDE):
Dunfield has a good reputation, one of my teachers uses it:
I spent abot 20 mins after doing a Google search. If you spend some time you
are sure to find stuff
There might also be a gcc (free) port too...