This file is free with a purchase of $20 or more.
This file is intended for printing at 24" x 36", but can be printed at any size. You can print this as a blueprint at a nearby printer. Printing it at Staples costs about $4. Make sure to print it in black & white for the cheapest price. link
The paper quality for these types of prints is pretty thin, but it works. Be careful with Sharpies bleeding through!