Borland have a free edition, but I can't say I would recommend it. Too much water has flown under the bridges. The compiler wasn't bad, but it really is many x86 generations old. And it isn't even simple to move 16-bit GUI applications to 32-bit with it. I did try some years ago, with very bad experience. Also contacted XX (whatever their name was then) about buying an old commercial license, but there was no way they could sell a license - even if I had access to the install CD:s and only wanted to pay for giving company B a valid license of a compiler owned by company A. The end result was a complete rewrite of the application instead of fighting the Borland route.

I haven't looked lately at the free Watcom compiler. Last time I looked, the download was temporarily (?) pulled while they did some rewrites - I think it did involve some problems with licensing of the MFC header files. The original, commercial, compiler was very, very good, but much have happened since then.

Microsoft have their Express editions. But it has a number of limitations - after all, M$ expects customers to want to pay for their commercial editions. I have tried it, hated it, and either switched back to VC6 (ancient but good) for old existing projects or Dev-C++ with MinGW or Code::Blocks with MinGW for newer projects.

When doing graphical applications, I normally use the wxWidgets framework, since it allows me to build for multiple targets.
http://www.wxwidgets.org/