Can I use alternative materials to insulate my roof?
Have been looking into shredded newspaper, pillow or mattress stuffing, polyfiber fill for quilts as I can get stuff like that cheap enough


That was the insulation of yesteryear. You can still tear apart some very old homes and find them lined with newspaper. So why did we stop using stuff like that?


Fire resistance. Newspaper burns like... well, newspaper. Standard polyfill stuffing will burn almost as readily. Fiberglass and cellulose insulation (which is ironically made from sources like newspaper) is designed to have some fire resistance.
Thermal resistance ("R value") - Newspaper is better than nothing, but it's thin paper. It's not designed to resist thermal change. Neither is polyfill. Polyfill has a slight edge because it can trap air (which is what most insulation does since air is a good thermal resistor) but it's still not designed to do that.
Pests - Most insulation is treated with something to make it somewhat resistant to pests. It won't stop a squirrel or rat from making a nest, but they won't be looking at cellulose insulation as a food source either.


I would save up to buy the insulation you need instead of trying to do this on the cheap.