Just wanted to share. ACMoore has 20 x 30 3/16 foam core on sale for 99 cents (reg price was 2.69 i think) until 4/2.
I just started using foam core so not sure if that is a good price, but it seemed pretty good to me.

I thought for sure the cashier would ask what the heck I was doing with it when I bought pretty much all they had