Sam's club is great for stocking up on bags. Things are sold in bulk here, so the savings are passed on to you! I visit here about once a month and I stock up on all sorts of things for my home. And among those thing are bags: brown lunch bags, ziplock bags, sandwhich bags, hefty trash bags, etc. You name it, they have got it!
I love Sam's Club because I know I'm saving a lot of money by buying this stuff in bulk. Plus, it saves me from having to run out to the store again and again when I run out.
Check out Sam's Club for other kinds of bags too. Once, I purchased a carry on luggage bag for myself from here for quite a good deal! This place rocks and the savings really add up!