I bought the last roll in town about a month ago (I also only think it is at Walmart) at the time. I got a piece of wood about 2 ft long and put a nail and thumbtack in for a template and that makes it fairly easy to make these "belts" other than trying to see this almost invisible thread and then tying the knot. I've seen the NZ video on the knot they want you to use but I'm not sure I could do it with this thread so I just do a double square knot (over and thru 4 times).
Edit: Just went to Walmart near me and found two rolls of the clear and several rolls of black.
Black might be easier to work with (for visually impaired old guys).