Q: What's a free or cheap C compiler I can use?
A: A popular and high-quality free C compiler is the FSF's GNU C compiler, or gcc. An MS-DOS port, djgpp, is also available. As far as I know, there are versions of gcc for Macs and Windows machines, too.
Another popular compiler is lcc, described on these pages at Virginia and Princeton.
A very inexpensive MS-DOS compiler is Power C from Mix Software, 1132 Commerce Drive, Richardson, TX 75801, USA, 214-783-6001.
A shareware MS-DOS C compiler is available from ftp.hitech.com.au/hitech/pacific. Registration is optional for non-commercial use.
Archives associated with the comp.compilers newsgroup contain a great deal of information about available compilers, interpreters, grammars, etc. (for many languages). The comp.compilers archives include an FAQ list and a catalog of free compilers.
See also question 18.16.