I've used MapTool for years, and though it's admittedly quirky you can't beat the price. While it's capable of running advanced tools, I don't use the macro capability or game system frameworks, just the basic map capabilities (including Fog of War).
The main RPTools site appears to be under DDoS attack at the moment
but you can download the latest version (1.5.14, not counting the 1.6 beta) at GitHub
here and there is a
documentation wiki available as well.