I went from this: a journal book from the Dollar Bin at Michael's
To this: using copied images from the notebook to make a card
A package of colored, high quality stickers would be at least $4.00. My notebook cost only $1 and I can copy it and have as many butterflies as I care to use!
The copied images look better, to me, than stickers since most stickers are glossy finished. They're very simple to cut out using Cutterbee scissors.
The Dollar Bins also had 3 x 3 and A2 sized note cards with different sized butterflies on them so I picked them up also. That gives me a variety of sizes as well as types of butterflies.
This is a great solution for me since I tend to make anywhere from 4 to 12 of the same card to donate to charity.
Another idea is to do a Google image search for something you'd like to use. You'll be amazed at the free clip art and photographs available online.