In many ways the easiest way to advantage of SBS is internet gc's. There's no need to ask them to swipe 20 cards you just sit there at home and input all the info.
Last year mostly music worked and it just worked for the big break promotion so I would guess that it would work again.
Also last year zundel Berman worked to buy Gc's online, but i dunno about this year.
Any other good ideas? Have the tzedkahs started advertising yet?