This website: http://gridzzly.com/#t allows you to print your own graph paper. I am not sure it is cheaper, but in a pinch, you can print out the graph paper you need.
Print as a PDF
I like to be paperless, this means the print option is not an option. However, I am able to choose to print to PDF. With a PDF of the custom graph paper, students can annotate on this on a tablet device. I can also take screenshots to obtain digital images of the graph paper I want.
