At the end of 2014, microsoft released a new liscence for visual studio.
Visual Studio 2013 Community Edition has some restrictions on who can use it:
small companies (<5 devs), individuals, open source projects, or academic use.
If you pass that, it is identical to VS 2013 Professional.
According to fsharp.org, VS2013 and above (including Community Edition),
include the F# tools.
Visual Studio Express
Note: some links here use the Wayback Machine, as the Fsharp.org website has been updated to recommend visual studio 2013 community. Other links have been updated. However the solution below should still work.
I used Visual Studio Express Edition, with the F# Tools.
This is basically visual studio, so it's pretty good.
Your main issues would be possible licensing restrictions.
According to microsoft, Visual Studio Express Does support F#.
Did you remember to install the F# compiler, sold (free) separately?