Oh my I am definitely a fabric hoarder. Lol. I have bought from:
Hobby lobby
Joann fabrics
Hancock fabrics
Walmart
Amazon
Etsy
eBay
Fabric.com
Local fabric boutiques
It's addictive buying fabric.
The best buy I have found on Velcro is on Amazon. I get 10 yard rolls of both black and white pretty in expensively. I buy d rings on etsy from a lady in china. I know I should be buying from American vendors to support the us economy but I get 200 d rings (100 in 1 inch and 100 in 3/4 inch) for right around $40. I just can't find prices that low from America. I also always use coupons and sales. Hobby lobby and Joann have a fabulous mobile app you can add to your phone for instant coupons. Hancock has a mobile club you can sign up for on their website where they text you coupons. If I ever do a big order I love fabric.com because they offer free shipping on orders over $35 I think it is.