I bought good strong strap material from Jo-Anne fabrics for around $18.00 It is very similar to seat belt fabric but not quite as tightly woven. Two years later they still serve me well.
Hi
Got mine last year from
http://www.strapworks.com/Polypropylene_Webbing_s/59.htm
I think the whole order, cut and sewn with loops was less than $25 with shipping. Liked the fact that I could choose a color.