There are layer cakes of I spy fabric. I've purchased them from Missouri Star Quilt Co.
http://www.missouriquiltco.com/shop/...ary-layer-cake
I'm sure they are available other places, too.
My LQS will also sell fabric in as small a strip as I want to buy. I've bought some I spy stuff that way, too.
When you get several purchased and cut you should have extra squares of some. Take your extra squares and try to trade them with someone. Someone like me would be a good idea. I love I spy fabric!