At a local stationary store I found initial ones, but the font used was Papyrus, which, like Comic Sans, is considered a terribly overused font. Online searching fared better and I found a place called Seasons Creations which did not want an arm and a leg for Canadian shipping.
The seal is just the cutest little thing. The instructions were easy to follow - moisten the seal on an ice cube or cold water and light the wick and hold at a 45 degree angle to get wax flowing. It was hard to guess how much wax would be too much or too little, but a spot about half the size of a penny did the trick.
I think next time I will use cold water instead of an ice cube. When it came time to stamp, the seal was stuck to it! But it was handy to put the wick out. Now I can't wait - just imagine all the ACEOs and whatnot I can send out bearing my own purple pony seal!