It seems like I’ve been posting about "engineering prints" from Staples forever - super cheap black and white copies in HUGE SIZES. Since they are printed on rolls you basically pay by the inch and an enormous copy will cost under $5. With a fixed width you can make your print as long as you want. Lots of them are on Etsy.
*Tip: call Staples or your copy shop, ask about prices, and ASK about the conditon of their copier for engineering prints. Our Staples told me that their copier was old, but the copier in a neighboring Staples was brand new.