I lucked out since foam was on sale at JoAnn at 50% off when I went. So I paid about $5 for 1 yard of 1/2 inch foam. The fabric I bought was 30% off and cost me about $5 for one yard (and I even have a little left over for another project!). Add in $1 more for velcro and my supplies came to $11! Love that price!
(I also love all the scribble marks on my cutting mat. We have a budding artist in our family.)
You can see that the extra lens I have fits perfectly in my little sectioned spot. And see that little section below it? Hopefully I will be putting a (new to me) lens there soon. I'm in the market for a 50mm f/1.7 lens. (Wish me luck on ebay today!)