That’s right. How to make dust bags for purses. Go me. (Note – my handbags are not expensive, fancy, or in any particular need of protection from the elements. But I *hate* reaching for a bag and finding it all dusty. Ew.)
Because dust shall not prevail in this household, I went to the Dollar Tree and bought some pillowcases. Note that these are not high-quality cotton pillowcases. They’re $1. But they’ll keep dust away, and that’s all I needed.
I also picked up a spool of ribbon. (So, technically, I suppose these dust bags cost $1.25.)
First, I found the seam along the open side of the pillowcase. The open side of a pillowcase has a large hem, and that’s what we’re about to get into.
I snipped it open with scissors.
I threaded the end of the ribbon onto a safety pin.

And that’s pretty much it. I was left with what looks like a gigantic drawstring pouch.
I put a handbag in, folded the excess material over, and tied the thing shut.
The old threading-ribbon/elastic/whatever-with-a-safety-pin trick! My mom taught me that ions ago when she taught me to sew. Glad to see you using it, too.
It's a good trick! I will not discuss my attempts with elastic, because they're not pretty. Elastic is the devil.