If you can't find a New or Used Windows 7 computer for a good price, or at all (Where I live there are 0 Windows 7 computers anywhere), then, yes... As a last resort, if having Windows 8 really isn't working for your
BL experience, you CAN purchase a copy of Windows 7 and install it on the same computer as the Windows 8 one. In fact, Windows allows you to install 2 copies onto the HardDrive. Dual boot! ^_^
That way, if you need only one OS for some things, you can choose to specifically boot into that version.
So, worst case scenario you end up with a Windows 8 computer... find it doesn't work for you (Or the game you absolutely wanted to play), and you can still find a copy of Windows 7..then that could work for you!