Treasure hunting is always fun. Garage sales are some of my favorite places to go scavenging. My Mom once found two large pea-sized cultured pearl cufflinks to be the real deal for only $2. The owner did not apparently know what she was selling.
My Mom stealth fully did the "real pearl" test - lightly scratch them against your teeth to see if they feel sandy or grainy. (P.S. May not want the seller to watch you do this). They seemed genuine and she doublechecked the price with seller.
Later, she got them appraised, and had the set remade into a beautiful custom ring set diagonally with the two pearls.
I have also found long strands of semiprecious stones for just a few singles. So keep your eyes out for estate finds and special treasures buried amongst the dusty wreaths and brass lamps.