generic

my local music shop has a selection of hard cases that have not been designed for any particular machine, i just chose the one, $40, that came closest to the sp808's dimensions, took it home and cut up some foam rubber cushioning to make it all snug. i attached the foamrubber with velcro so it is easily removable and i can use the case for other toys as the need arises.
your b/friend is a lucky guy.
this is probably your cheapest option.
i'm sure some other users here can tell you some companies that make sp808 specific cases.