It really doesn't get any easier than this! I'd completely forgotten I had the Watercolor Wonder card bases from the Occasions Catalogue, so when I went to go make a birthday card for a friends and ran across this lovely post by Patsy Waggoner, I went digging for them. All in all, it took me about five minutes to make this card, including looking for the bases.
The card bases are still available but only until May 31st. It's a set of 4 each of 5 different designs, so you get bases and envelopes to make 20 cards, all for only $15.95. Easy peasy right? Take a look on the online store!