I have used plastic canvas for tote bag bottoms, so I'm sure that would work in a purse as well. I received some clear plastic cutting mats for the kitchen at Christmas and as I looked at them I thought - purse bottoms. They are light weight and I assume they would be easy to cut, haven't cut one up yet though, so can't say for sure. Hope this helps.

I do, too, and I've never had them bend. I cover them with the lining fabric or coordinating fabric and they are very light weight.

I took a class once and the instructor had plexi glass bottoms that she sold them to the students for $1 each. She had them cut at a local shop here in Stockton, CA called "Tap Plastics" She told me they will cut and smooth any shapes you need.

This is what I have done too. They are pretty cheap (under $1 for a 12" square) at Lowes or Home Depot.

I recently needed larger bag bottoms and got some corrugated plastic from a sign store...but after this year's elections I plan to pull up a bunch of the signs and use the plastic!

I do exactly the same. Can usually find odd ones on sale
at Walmart.

My quilt guild had a speaker/workshop "Lizz Ploppert" who uses Plas-Tex which is shower stall walls. You buy it at home improvement stores and you can cut it with scissors. I bought a couple of her patterns and she had enclosed pcs of the plastic. It is a 3-d birdhouse that will open up into a mini-wallhanging. This plastic would make great purse inserts. I think she said that it sold in 4' x 8' sheets and you could probably have them cut it in half for you. She suggested you go in with a friend and share the sheet.

I recycle my old cutting mats for purse bottoms.

I have also used 2 layers of peltex also. Works well.Just buy it off the bolt at your local quilt shop.

I looked into the bottom of my expensive Vera Bradley bag....they used cardboard!!!!! Just regular cardboard!!!

I cut and use plastic note book covers I cover them with Purse linning material and they can be washed in washing machine even dried on low temp setting

Plexi glass works well inside a fabric casing. You might even glue some batting to it for softness. I went to the hardware store, and they had leftovers. I told them what I was looking to pay, gave them the dimensions and they cut a piece for me, was I happy.