I use the foundation stuff from JoAnn's and use my 40 or 50% coupons to purchase. I did do some reading somewhere, maybe even here, where some are using what is called Bank Paper purchased at a copy or printing business. Suppose to be lighter then typing/copy paper. It's on my list to try.

try freezer paper or baking paper, you can buy them at supermarket.
Freezer paper is better as has a shiny side that helps it stick to the material when pressed. I buy the generic brand as works as well as other.

freezer paper??? I have not done paper pieceing yet sorry if I am wrong

freezer paper is used between layers of food when freezing such as hamburgers. It is sold on a roll in a box the same as aluminium foil is.

You can also use adding machine tape.

End rolls of newsprint paper from a local newspaper work well. There is no ink, and you can cut pieces to any size you like. Also use a shorter stitch length to help get paper out afterwards.

Parchment paper. You can copy the pattern you want to use and it can ironed onto the fabric to follow. It tears away simply.

I buy vellum paper at Staples.

I buy rolls of the tissue used by doctor's offices on the tables from a local medical supplier. It's sturdy but very light weight and its really cheap. I use it for packing glassware and making my own patterns too. Each roll is over 100 yrd and runs $3 to $5 depending on the width.

Thanks. alot of good ideas for different papers to use for paper piecing.