It's time for a lot of us to quit worrying about our UFO's. Maybe it's possible through this board or local quilt guilds to hook up with someone equally jaded and you could trade UFO's. Or donate them to a quilt guild that sews quilts for charity.
If there are any quilters near you, maybe your shopping trip could be car-pooled and would be all the more fun.
I just figure collecting a stash is part of the entertainment value of the hobby and don't worry too much about it, but I'm lucky enough to have a DH with a very expensive hobby of his own. Good grief, the price of a beer after a round of golf is probably equal to more than a fat quarter or two. He recently went to Las Vegas with a golf buddy. So I should worry about the cost of a little fabric? Don't think so!
Too many women have a tendency to feel bad about the little things we do for fun. If you are not cramping the family budget with out-of-control spending, just cut out the guilt trip! If you really can't afford it, that's another matter. Perhaps you can make some items that will sell on Etsy to support your hobby. Whatever you do, don't make yourself miserable about quilting. Either you love it and deserve it or you need a different hobby.