U-line doesn't seem to bad.
https://www.uline.ca/BL_1953/Newsprint-Sheets
The stuff the pros use is the 24"x36", it comes in 25lb bundles for a little over $50.00
I don't know if it's still a thing but you used to be able to go to a moving company's warehouse and they'd have big boxes of used paper from after they have unpacked a customer. They keep it to use as fill but they end up with way too much of it to re-use.