you might do, but cased means nothing. look for a mechanically intact example foremost, unless its just for display. try ebay USA ,more to aim at but quality varies hugely. 30-40 quid will get you a razor with either mechanical or cosmetic issues, look at 50-70 for a presentable and fully functional item. add 10 and up for a case.
in my experience they are overrated, the slim adjustable is a much better razor, as is the super adjustable. as always YMMV.
the slim is closer in design to the super than it is to the fatboy.