I buy full-size and split down the middle. They come in a box of 1000 sheets
and one full works perfectly when making a pie....I just fold half over the dough to roll and don't have to add extra flour.
The shipping and parchment costs when buying 1000 can be shared/split amoung friends. Cost is ~$31 for 1000. Not sure what shipping would cost.
When doing gingerbread, I split the paper in half and sandwich the dough, placing wooden dowel spacers to keep an even thickness. After rolling out and removing the top sheet, I cut the pattern, pull away the excess dough and slide the entire bottom sheet onto the cookie sheet to bake.
When making cake circles with ladyfinger batter, I flip over the parchment and trace out the cake pan sizes. Then flip over and pipe the dough with a 1/2" opening (or no tip at all...the pastry bag opening is typically large enough).
I recently posted how to roll up cookie batter into tube shapes using parchment, then roll up the ends and store in the freezer.
I just love parchment.