My sincere condolences on the loss of your husband. I can only imagine your pain.
To build up your stash, you can buy 1/4 or 1/2 yards of fabric when it is on sale. I also bought the fat quarters when they were on sale. Sometimes, when I find fabric I want to use for a specific quilt, I buy an extra yard to add to my stash. Before I knew it, I had a humongous stash.... good luck!