Just as in many other California communities, a ban on single-use plastic bags has recently gone into effect in Pasadena. Those bags are big polluters so I think the ban is a good idea. The ban doesn't cover all stores, but I can't keep track of which stores it's in and which it isn't, so I carry my canvas bags everywhere. I've been doing it for a while and I have a collection in the back of the car.
You play your cards right and folks give 'em to you for free, if you don't mind a logo. I've got one from the City of Pasadena, one from Whole Foods, one from some book fair a hundred years ago, several from Bell Sound and about a hundred Trader Joe's paper bags that just won't quit.