Apparently they are also called "old man sacks."
I've been using them since I was a kid. (In the 1960's. That's right: I'm an old monkey.) I was hoping to be able to continue using them. I suppose I'm what is known as a creature of habit. The one I have now is 20 or 30 years old, and it still works fine, but it's been starting to to crack and split. For several years. Making me think that perhaps it might not last as long as, for instance -- me. So today I went shopping for a new one, couldn't find one anywhere, expanded my search to include pocket sized things which could be zipped shut, still slim pickins. A few friendly salespeople in my advanced age bracket knew exactly what I was looking for, and agreed that what I needed was something like a time machine to take me to 1965, or I was probably going to have to make do with something else.
I returned home, saddened, feeling like Chingachgook. But then I remembered: of course: AMAZON! They've got everything but guns and real estate -- unless they've expanded into those things too. Even there, among many, many coin purses, some of which looked really nice and were made of things like rough cowhide and hemp, I didn't see what I really wanted until I got more specific and searched for rubber coin purses, but then, sure enough, I found a truly wide variety of them.
Oh btw your local Home Depot may have some too. I just say that because the photo above is from Home Depot's website. Maybe hardware stores in general have old man sacks. I don't know.