I am in the same situation.. I started my own chapter of Quilts For Kids and I have to be "thrifty" on what fabric I purchase. We do get fabric donations but I still need some "filler" fabric to fill things out
I don't know how you feel about your projects, but I try to get decent fabric but I don't feel like I need top of the line... I just want it to hold up.
I have not seen where a certain brand/manufacturer has a cheaper line to sell to lower end markets. My experience is that those are different lines. They could be made in the same factories for all I know - but they have a different name/line they sell under