I bought one of those refurb HP SFF computers from Micro Center for $65 with W7Pro on it open box. (The store is local for me.) I took off the top case cover, removed the pci slot extension, cut the back panel with shears and installed a regular full size video card in it with HDMI out that was mothballed from a past build.
Ugly but effective, and cheaper than buying an OS by itself! A PI2 would work for me, but I like the DRM enable I get for passing along cable TV with HDHomerun 3 tuner card through Media Center.
The only way to get Media Center is with W7 or W8 with Pro or Ultimate. Upgrade to W10 and kiss it goodbye!

This cheap rig becomes my gameroom HTPC and the I5 machine will go to the gaming build.