So far I've only tried to find bulk dried black beans and dried kidney beans on S&S, and it always works out cheaper to get them locally from my local natural foods store or even <gasp!> Whole Foods dry bins. I'd love to buy these online and be able to stock up more easily, but so far not worth the cost.
I also find that TJ's has the best price on nuts, shredded coconut, raisins. So far.
ETA: We use Subscribe & Save, don't have Prime, so just occurred to me that our pricing options might be different.