I actually use a variety of items rescued from the trash, most of the time. There is 1 kind of cardboard box that has smaller 'corrugations' in it than the regular shipping boxes. I cut 2 pieces to the size I need and cover it with lining fabric. I've never had a purse bend and it seems to work fine. Also, I left a cutting mat in the car and it warped badly in our Texas heat, so I cut it into strips to use for purse bottoms. Sometimes I use that plastic canvas if there is a large enough piece left after the original use, and I've also used foam poster boards. All of them have worked for me.

I used the plastic canvas and round the ends and cover it with fabric. So if it gets wet it really won't matter, but I leave the cover open on one end so it can be washed. :):):)

I use these plastic chopping mats from the Dollar Store, cut to size (and stacked, if I want a really firm bottom). I generally cover them with a self-fabric lining also.

Leatheflea, you stated that you used plexiglass and cut it to size. What tool did you use to cut it. I am having a hard time cutting mine. Thanks for your help.

Robin,
It may not be the right thing to do, but I have actually used insulbright in the bottom of some of my purses. It gives support and it is washable. I haven't tried to wash any yet, but that is what I had on hand and that is what I used. Sue

For larger handbags, I have used a thin piece of craft wood covered with fabric ( like Vera's) I got it at Lowe's. Joann sells purse bottoms now.

I have used plex-a-glass cut to size, covered leaving an opening to remove for washing. The last few I have made, I used PenTex with an additional heavy interfacing sewn into a sleeve that is attached to the bottom end seams...does not have to be removed to be washed and also does not slip around the bottom of bag. Tons of idea out here.

Judy in Phoenix

This is what I use also. It works well I use a zig zag stitch to install on bottom of the lining. Dottie Bug

Michael's carries the 1/8 inch plywood. It can be cut with a craft knife or box cutter. I paid $2.00 a sheet and it was big enough to do four mini bowtuck bags.

Someone posted (maybe here?) they got their hands on an old cutting mat from a quilt shop. It was full of cuts and a bit warped so they were going to toss it. it worked really well in bag bottoms.