If it happens where I live I’ll just go on-line and buy myself a large quantity of plastic bags and take some with me when I shop.
.
I did that. Bought a case of them off Amazon. The key is to remember to take them in the store with you. Took me about a year. Every time I’d get up to the register I’d think damn! I forgot my bags again.
I still hate having to take my own bags.