I used to run bookstores. Bookstores frequently have books to give away, if you don't mind detached pages or missing covers. They get tossed or sometimes used to start the wood stove. Same will apply to library sales. I'd ask the week before the sale, likely when they're processing the donations. I have made paper mache of falling apart paperback pages before. There used to be a website which listed library sales? Try book sale finder dot com .
The power companies here have trees cut down along the side of the roads. An obnoxious neighbor gleans almost everything within 10 miles. He's not real careful apparently about whether the wood belongs to the house there, or not, either. Like the fruit in the alley, something to consider.
We went to a high-end appliance store in Boston one Sunday, not too long ago, to look at refrigerators. Ours, which the manufacturer had replaced as the one we'd had 3 months died, was on the fritz,. We had no faith it would be fixed any more than the original one had. (It was.) So, we were starting the search for features vs money, again. Anyway, we had a nice, free, hand lunch. Quiches, coffee, breakfast cookies. Completely surprised us.
Fabric: around here "logo" tshirts are free or real cheap at thrift shops. I guess there's a law or something. I used to make t shirt yarn mats, was the best source I found for that.