I re-use zip top bags whenever I can. I use them to bring sandwiches and salads to work. DW rolls here eyes when I stop her from tossing the zip-top granola bag. Those bags last a long time.
I'll stop her with "Oh, wait .. that's a good bag, eh". I don't know why, but it's funnier when I say this with my thickest Canadian accent. Now she preemptively apes me as she stuffs the bag into our dedicated bag drawer.