I had a bunch of these 4" coasters and I'm sure I saw this in blogland somewhere, but not sure exactly where? I just used some of my SU! designer paper. I cut my paper a little larger than my coaster, cut off the corners, and overlapped the extra onto the back side (I used double-sided tape for all dp). Then, I cut the backside with coordinating dp and cut slightly smaller than the coaster and taped it over the over-lapped pieces. There might be a better way to do this, but I wasn't following a tutorial, just making it up as I went along. It actually does show the corners a bit :(
I used a sheet of letter stickers, but only had one sheet of them, so I had to really choose the words carefully. It turned out okay though. The only part I stamped was the piece on the front.