I’ve found a good use for those return envelopes that come with bills. (And, yes, I still get paper bills unless the issuing company charges me for them. I keep them on file for tax purposes, for comparison purposes and, no, I don’t want to use my own paper and ink to print them off.)
Since I pay virtually all our bills via online bill pay or auto pay I used to throw the return envelopes away. But I’ve started to use them for my grocery lists, tucking the coupons I plan to use inside the envelope.