I use re-usable canvas bags whenever possible, but I quite often order my groceries, etc. in when my arthritis is acting up. They, of course, come in plastic bags.
In the old days, they were great for dealing with litter pans. However, since I've switched to a silicon dust-free litter to spare two wheezy cats' lungs, I scoop much less (the litter dehydrates "things"), and I'm beginning to find myself inundated in bags.
Since our apartment building has no-sort recycling bins, I've been putting them out with the rest of the recycling, but I have no idea if they're actually being recycled.
I checked to see if the two grocery services I use had the option of using paper bags, but they only use plastic. At least with the paper I'd KNOW they were recyclable.