Selling your fabric at the garage sale you mentioned may, in my opinion, be the way to go. Since you mention storing your stash in plastic bins, even tho good quality, it may be damaged unless you've drilled many holes in the plastic for air to flow, and have re-folded from time to time. You may want to check for a local quilt guild and ask for their advice; quilters are very helpful, friendly people for the most part.
Good Luck