This page has links and descriptions of compilers that are freeware, shareware and retail.

DJGPP is a complete 32-bit C/C++ development system for Intel 80386 (and higher) PCs running DOS. It includes ports of many GNU development utilities. The development tools require a 80386 or newer computer to run, as do the programs they produce. In most cases, the programs it produces can be sold commercially without license or royalties.

The Free Borland C++Builder Compiler is a 32-bit ANSI C++ optimizing compiler for Windows. It includes the latest ANSI/ISO C++ language support including the RTL, the STL framework with C++ template support. What I use.