I've seen this done and I think I even pinned about it. It's just two pig-shapes cut from felt. I sewed a buttonhole using the largest setting (the thing you put the button in, which I just opened up all the way without a button) to make the slot for coins.
I looked up 'pig' and found a simple drawing that I copied for the pattern. I think this would be a cute way to give some birthday cash to a kid--maybe with some change inside and a bill sticking out through the slot. You could even put it in a birthday card since it's nice and flat!
Oh! I stuck a piece of pipe cleaner between the layers. You should sew over it very slowly if you do this. Even though pipe cleaner wire is fine, you wouldn't want your needle to hit it directly.
I wrapped the p/c around a narrow knitting needle to make the tail.