I agree with margiepink. I avoid Walmart like the plaque because I have had so much trouble with purchases from them. Their quality and measuring usually are poor and inaccurate.
I do this too, have a box full of velcro in different colors. Comes in handy when I need it.
I buy velco (sew in type) by the box, comes in a large roll and when Jo Ann's Fabrics has a 50% off coupon. Same as for stabilizer always use the coupons. If you do not have a store near you log onto Jo'Anns and print out a code for online purchases.
I do not have a JoAnne's nearby but I will check out the online option. Many times though I find that the shipping eats up any savings so I might as well buy locally and I don't have to wait for it.