OK, if you're gonna make your OWN floats, here is the best link I ever found for that.
http://www.flyinglindy.homestead.com/skisandfloats.html
you can get the 1" insulation foam at Home Deepo and laminate 3 or 4 layers together to make floats. Cheap. Get "Gorilla Glue" while you are there. Not Cheap, But really, really good.