For paper piecing, I bought a 3 pack of newsprint sketch pads at Staples, went to the copy shop and had them cut 1/2 inch off width of the paper so that it would run through my printer. the pads of paper were relatively cheap, and cutting all three of them only cost $2.50. the pads were 9 x 12 but I only cut it to 8.5 by 12, the extra inch wasn't a problem with my printer, or you can tell your printer you are using a custom size paper and change the size to 8.5 x 12 Can print my paper piecing designs on this, and it tears off much easier than anything else I've tried, including paper sold as paper piecing paper. . My daughter in law has done 2 large paper piecing quilts and the pieces were printed on newsprint.
I also use this paper to print applique designs and quilting and embroidery designs on so that I can just sew over them, works great. I did several gift bags this way for Christmas
I imagine you could by reams of newsprint paper online that are the standard 8.5 x 11.