personally, my decision to use carpet was not because I couldnt' afford underlayment....but it was to save money. I don't see the need in spending money when you can get a different product that works just as well for free. I DIY everything, and always look for ways to cut costs without cutting quality. But you're right....if you cant AFFORD underlayment, then don't start. Underlayment is cheap compared to the rest of the costs. Ain't nothin' cheap about building a pond!!