Bag Making Question - Fabric problem - HELP!

[EyesDoMoreThanSee]

Hi
I have just bought the Lisa Lam "A bag for all reasons" to create some Christmas presents, I am intending on making the bicycle panniers amongst other things. I went out today to cost up the materials and found that the laminated cotton fabric was £10 a meter but the PVC Laminated Fabric 50% Polyester was £3 a meter.

What would happen if I used the cheaper material? Do I have to use the laminated cotton?

Because if so I might as well send the book back because I cannot afford to buy the materials!

Thank you oh wise people

If it's the type of fabric I'm thinking of, the cheaper PVC will not be as strong, and also has a tendency to tear when sewing it (I tried to make a cover for a high chair once).

Do I have to use the laminated cotton?the cheaper PVC will not be as strong, and also has a tendency to tear when sewing it.