I looked at them today again. Almost bought a set, but just couldn't bring myself to do it. I agree, a piece of cardboard would do the trick also since it's just tracing and cutting out with scissors.
I bought a book "String Quilt Revival" but after I got home and really looked at it, I think I'll return it. It looks like Bonnie's Quiltville and Mary's string quilt ideas. Nothing really original.
I get too excited about coupons and sales. I did pick up several rulers-6.5" EZ angle, tri-rec ruler, companion angle and the easy circle cut.