Welcome Leslie. I don't know if they have estate sales near you, but these can be very good ways to boost your fabric stash.
I search terms like "sewing" and "quilting" to get good results. Quilters often have stashes from their mothers and grandmothers (and friends and neighbors).
If an estate sale runs over several days you'll find the best bargains on the final day. Bring tote bags or garbage bags with you - often they'll let you take a whole bagful for a super affordable fee.
Glad to have you!