I don't get bulk grain, but I use the food saver to vacuum and seal leftover DME, adjuncts and hops. Someone has pictures of how they foodsavered 50 lbs. of grain.
I store small amounts of grain in vacuum sealed bags in the freezer. I store my large bulk grain bags rolled up and clamped shut in the basement. I'm hoping I use them up before they go stale. Although at the rate I've been brewing, I better re-think my strategy.