If you can get free materials, then sure, you could save doing this. Just a LOT of work though, and you have to factor in time. Can't make any more of that resource.
Still, it is cool that one could make it themselves. I'm a big do it yourself-er, but I always have to consider time and cost and weigh that accordingly.
Right now, for example, I want to repair a water line, and run an additional one. The materials to do it cost me $50. I couldn't even get a plumber out here to LOOK at it for that price, so of course, doing it myself is a no-brainer.
(should also give me a chance to show the kids a thing or two about doing things for yourself too).