How much time will you spend making this throw? Will you have to square it up? Trim? Sew? Quilt it? Measure? Bind? Set up your machine? How much thread? Is it good quality material or will you be working with something that more challenging? Is there a deadline? Do they want anything special? How much are you worth? How valuable is your time? Will you be washing it before returning it?
So many factors go into pricing our time, even the simplest of items requires time and effort far more than we ever think about!