I have ~15 soaps. Don't use all of them, and some I haven't even tried yet. (I also use a few creams)
Storage varies:
original soap container (plastic, ceramic, wooden, pewter bols)
Ziplock bowls
Ziplock bags (the ones I haven't even tried yet and just received like this)
little glass bowls (w. lids, but lids got lost; these I got from my wife, not sure but I think they were originally intended for storing food)
No soap of mine is in a mug. I don't own a mug, actually. :shrug: I use either a dr. Moss scuttle (and mostly lather on face) or a pot I got from Le Gourmet Chef (for whipping lather).
Cheers
Ivo