One note about thrift shops... I have a local quilting friend who buys much of her fabric at thrift shops. She is thrilled. Granted, it is sold very inexpensively. I don't know if they go through a cycle with fabric as most thrift shops are wont to do with other items - x days in the shop at their full price; then x days at y discount; then the z $/lb table.
I only buy for projects. My 'scraps' are, to my friend, 'yardage', lol. She does much charity sewing so all of the above are great finds for her. I keep a bag/bin on hand and as I finish a project any leftovers go in there for the next time I see her. Works for both of us.
Another friend recently needed to purge her sewing room. Much of her leftover fabric was 'donated' to my other local friend knowing (by the purging friend) that much of it would be used for charity quilting. What she (the local sewist) is not able to use she will donate/freecycle to others.