David from Cheltenham Road is all about retro coasters, his Etsy shop is full of them. He shared his methods with Mod Podge Rocks, using vintage comics for his graphics. The great thing about using comics in design is their versatility. You can go colorful, black and white, old school, modern--you name it, there is a comic out there that will fit the bill.
This project is pretty straightforward and uses an unusual but readily accessible material for the base. Choose your comic, break out the Mod Podge and you'll have custom coasters before you know it.