the cosmic law of coupons is that they'll usually not be be good for the things we need right now.
strategy and timing are the key.
make a list of the things you know you will need vs. the things you need or want now. shop the sales for the "now" things, and use the coupon for the "sooner or later" things.
maybe you can also learn from wolves.
they hunt in packs.
quilters eventually need two high-priced items for every project: batting and backing fabric.
if the cost of a roll of batting is outside your budget even when half off, maybe you could purchase it jointly with a friend.