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This first one ended up being a half pillow case dress, because one of the pillow cases had damage to the top portion. However, I had some pink fabric that matched it perfectly. I came up with the back without a pattern:
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When she grows some more, all I have to do is changed the straps and take the button and loop off and she'll get some more wear out of it.
I may not use the same exact pattern, or even a true pillow case but I would charge $10-$30 for a pillow case dress, depending on size and detail.