Yes, you can use scrap fabric if you have enough for what you want to make.
As for the material, look at yard sales, I love Church sales and Estate sales. Look for old sheets and medical scrubs, they come in such yummy colors!!! Old men's shirts, no matter where you can find them. Ask family and friends, probably they have a lot they don't want and don't want to throw away. Tell them to throw them your way.
Old jeans makes lovely, warm and long lasting quilts. Men's flannel shirts are thick and warm too.
Good luck and keep sewing. Enjoy what you are doing, show us what you've done and feel good about what you've accomplished.