This is one of my favorite projects that I have done recently because it is (1) cheap, (2) easy and (3) practical. They make great gifts too! Pretty much all you have to do i Mod Podge scrapbook paper onto tiles then spray it with a clear sealant. I finish mine by hot gluing craft foam on the bottom so they don't scratch up the table, but you could use cork or felt too. The tiles are just plain white ones--I got some at Home Depot for like $.12 each and my mom got me some for even cheaper at our local Habitat ReStore. Here are some pictures of coasters I have made for myself and for others.
To gift them, I simply wrapped them with some ribbon. It couldn't be easier!