I buy my parchment paper at the dollar store, a 1x25 foot roll. I use it for a lot of things.
In quilting since I have vision issues I will often draw my design on the parchment paper and quilt through it. I can see the lines so much better than anything marked on fabric (especially since my quilts tend to have a lot of small pieces and contrast) and there is the added bonus that you can't see when I go off line. Works best with a long arm but can be done with a standard machine too. The paper is tough enough but tears through the stitches easily.
You can use it for foundation piecing, better than newsprint or copier paper. It is clear enough that you can easily see through it for tracing.