There are so many wonderful ideas here it will keep me busy for a long time. Thanks to Rush'd Lady for sending me the link.
Off to do some more reading.
I think these things have been mentioned but these are a couple of things I do.
Use cereal boxes as thin chipboard or as kraft card for card making. Cut the ribbons off the inside of shoulders from my new tops. Toss all those spare buttons attached to new clothes into my craft collection. Use lettering from magazines to spell things out on cards.