I designed it in terms of adjusting templates. The basic forum is free here:
Simple Machines Forum - Free & open source community software
Then I downloaded some mods and had to edit some source files to change the menus at the top and other little things like that. I also wrote some custom PHP pages and scripts for my league but you won't need to do that. I also used the SimplePortal SMF mod here:
SimplePortal
That's the only one I think is absolutely necessary for what I have going on. Helps you tweak the layout, etc.
Other than that for just hosting I use HostMonster. Getting the actual server space and name may be pretty cheap if you're only using it for the file storage and transfer. I haven't looked in a really long time.