Beth, I don't mind smaller pieces, or piece. I too like the challenge!
I am working on my block, I figured it would be fun to make a few. I was a little short on the fabric I bought when I was in Washington so when I was at Walmart I saw some and bought it! Not realizing it was a different back ground color, so some will get Pink back ground and some will get lavender, but I would like all to use the Green Blue and Pink Neon from the butterflies. If you don't have any of those colors maybe a white or a WOW... No biggie, what ever works!
I took mine to PO and had the clerk check to see if the postage was right, she said yep, it cost me 66 per envelop, I got the event envelopes from Walmart, and for the returning blocks I got the manila envelopes, the clerk told me the 66 cent stamp should work on them also, depending on the weight and the thickness!