Actually, I think it depends on your local JoAnn's Store. Some will allow you to use the VIP card on the entire purchase even when you have sale items and coupons. Others I've found will not allow it to be used on anything except full price merchandise.
I get aggrevated with them since they will put out 40%coupons and have fabric at 20 to 30% off so the coupons are useless unless you need something that is not on sale. They know what they are doing. They make more that way and some of their fabrics are not that nice for the price they are charging. I still miss the olds "Piece Goods Shops". They had better fabric and cheaper prices.
Another thing that bothers me is that they are very careful to make sure they don't cut even the tiniest amount over a yard and when you wash it you have less than a yard if it shrinks at all. When you go to the quilt shops they usually cut at least an inch and sometimes two or three inches over the yard so you are not short. And the prices aren't that different anymore.