I know what you mean. I too am a tight budget quilter and have found some ways of collecting material that might work for you. I use sample books from furniture stores and wholesale furniture makers. They have pretty fat quarter size blocks and smaller blocks in them if you can get enough. My niece, who lives in Georgia, brought my sister and me bucket and bags of material and books from this furniture makers warehouse. They were throwing it away. We make beautiful quilts from the material.
Also, I ask at my church for any one who plans on getting rid of old clothes, especially men shirts, print skirts, etc. I lucked our on that also. I recycle a lot to get my quilts made. This might help. My challenge is stowing the material and using it up before I am bombarded with more. Happy quilting.