Right around the corner from Campion on Chausée d'Ixelles there's a place called Cash Coverters which sell consumers cameras and SLR's in decent, working shape* for dirt cheap. Friendly service, too.
(*Example: I bought an Olympus mju-1 which works OK (cover sticks a little)
for 20 euros with a case! Satisfactorily sharp, and gives correct exposures. I won't swear that everything you buy there will be perfect, but I remember that they offered a guarantee. Ask them about this and of course, check things carefully!).