Whatever you do, do not refridgerate. I have never bought in bulk, however I have kept waxies alive for 6-8 weeks by simply keeping them in a bait puck by the door that opens into the garage. This area of the house seems to have the correct temperature to keep them alive.
I do plan to buy bait in bulk this year, I purchased 2 of the big bait pucks to be able to keep the bulk bait in these containers.