Way back when I owned a store (we're talking mid-to-late 1990's), Magic was big back then as well. We had a space set up for gaming tables, since we sold Magic, and we did well pre-selling new release boxes, unopened boxes after release, and packs regularly from numerous sets (not just the latest), as well as single cards (we had a whole display case set up for singles). It was a heavy driver of revenue for us pretty much every day of the week (we had become a destination store for a lot of local players who would come and play there), and when new sets released, the sales of MTG would dwarf what we sold comic-wise (those were VERY good sales days ).
We would also run tournaments regularly on Sunday, and we'd charge anywhere from $5-$10 per entry (these were almost always tournaments that involved players playing with there own decks, often testing them out in competitive play before entering larger-scale tounraments, and we'd draw anywhere from 10-12 people on the low end to 25-30 people on the high end). We would take the entry money and disperse it to the winner and 2nd place in the form of store credit -- which almost always had the winners using that credit to purchase packs at full retail or single cards (which were sunk cost at that point). The tournaments were a nice source of income for our store on a day that many times could be very slow.