For sewing purses and pouches, I really like 12-16 gauge vinyl.
It doesn’t hold wrinkles very easily and it is sturdy without being too stiff to work with. If your project will require turning inside out and back again, you will probably want a thinner vinyl in the 8-12 gauge range.
Top Seller is the 16 gauge vinyl.
To make your vinyl look smooth and wrinkle-free you can iron it with a warm or medium-heat iron if you are always careful to place a press cloth in between the iron and the vinyl.
Or- Just use a spare fat quarter (18’’ x 20’’) piece of cotton fabric. Sometimes I press my vinyl (using a press cloth) before starting to get out any wrinkles that happened during shipping.
I also press while sewing if needed – still using a press cloth to make sure that the hot iron doesn’t touch my vinyl.

Use a Teflon foot to allow the foot to easily glide over the vinyl - no sticking.
After pressing, let the vinyl lay flat on your ironing board for a few seconds to cool off.
This helps it keep the flat shape that you pressed it.
When sewing with vinyl, try to use clips instead of pins, especially on areas of the vinyl that will show. The holes that pins make won’t heal up like they do on fabric.
When attaching vinyl to the underside of a zipper,
Wonder -tape double sided sewing adhesive is a great alternative to pins and neither will shift!