I bought these coasters from a charity shop for a few pennies. They're a lovely size, nearly 5" sq.
I decorated them using emulsion paint, handmade papers, stamped tissue paper and a bit of gold paint. I didn't decorate them in any particular order, just painted and glued as I went along until I got the desired effect. I finished them of with 3 coats of varnish. The main stamps I used are by Crafty Individuals.