you're right. that is a GREAT price. probably the best price i've seen.
the reason i don't use vellum is the price. even with 8.5 x 11, you can't get 2 6" blocks on one page. there's so much waste that when i practice, i use the cheapest stuff i can find. if i ever get good at it, i'll still use inexpensive paper.
on youtube, i've seen instructors say that they use regular printer paper with very small stitches and that works, but at the shows they seem to all use vellum. unless the sell carol doaks paper.