Hi Stephend. It's not a question about being smarter to buy or to make, it's about the enjoyment of making something with your own hands. If you have the desire and will to make your own mirror/telescope then do it. If it's a question about saving money then you won't because Dobsonian telescopes are very cheap these days. I have made several myself, because I like making the mirrors and building telescopes. It's not for everyone but if you want to make one then by all means go right ahead. Just follow the link that Garyh gave in the previous post for the materials. Just beware of apperture fever.
Cristian