VINYL TABLECLOTHS!!!!! Really, it's so logical. They are fused on the inside with cotton and the vinyl is the right weight to make it comfortable. I got this one for $2 at Wal-Mart but you can get them anywhere. This one is 60x84 so I can get at least 5 or 6 out of this one piece. I found a simple pattern in the craft department for children's vests (because, after all, a smock is just a vest turned around backwards) and got to work. Since this fabric is already lined the sewing took about 5 minutes. Basically, you cut out the back piece on the fold and then 2 pieces for the front. Stitch the shoulders, then the sides and you're done.
Here is a picture of the front (which is actually the back because you turn it around. Make sense?).
Then, I added a velcro tab piece on the back to keep it in place.
And there you have it. A perfect paint smock for about 50 cents! I'll be making a set of these for my art center for sure!! Enjoy!