I have made two sets (I need to source more coasters to use to make more) so far, one with my Double Yellow Lines photos which I also have for sale as a sweet print set:
Here's how they look as coasters, I've given them three coats of semi-matte varnish and they have a slight textured finish, I think they look great!
I've also made up a set with my Heart and Love Graffiti pictures (also available as a six part print set)
This particular set has been featured on the excellent Midday Masterpiece blog - you can see all of the other lovely graffiti inspired pieces here! Thank you to Melissa for featuring my work.