I use the corrugated plastic old campaign signs, round the corners and slip in a sleeve. Out of the landfill and an eyesore after the elections.

I use "InnerFuse" heavy weight double-sided stiff fusible interfacing wrapping the fabric around and fusing and bought at JoAnns and Hancock and always use a coupon and it makes a very stiff bottom.

Foam core board looks like two sheets of poster board with about 1/8" of foam pressed in between them. You can purchase it in most craft, framing, hobby or office supply stores. Sometimes I even find it in the local dollar store.

Here are a couple places to purchase the plastic canvas:

Plastic canvas (.79 to $1.89) available at:
http://www.everythingplasticcanvas.c...-mrl-c260.aspx

Create for Less has it from .59 per sheet, but must be bought in multiples of 12 sheets, at:
http://www.createforless.com/search/...astic%20canvas

Yarn tree has some, but pricey:
http://yarntree.com/cross-stitch/ind...646c818bdfdc80

It's foam core for me. Quite often I get it for nothing when we have a group leave the conference center.

Kathy

I use paint sticks you can get from most places that sale paint. I get them from wal-mart and Lowes. I just ask for a stick or two everytime I am going there I have a few put back for when I need them . I sew a cover to cover the card board and cut the paint stick to fit. craft knife works. and any box you can find. cut out the size of bottom of your tote. I like FREE!!!!

Ooooooh, thank you :)

HUSBAND CUTS A PIECE OF PLEXIGLAS AND IT WORKS GREAT.

you can also use the board in those broken notebook binders.

I used to use plastic canvas from Hobby Lobby - Ultra stiff large sheets. These days my husband cuts from sheets of plexiglass we buy at Menards. I like the plastic better, and use scraps from the bag to cover the base. This means they are often scrappy, and make a brighter bottom.