I went to an estate auction, mostly to get an idea of land prices, but also to check out the jewelry. There were several trays of mixed jewelry, and each entire tray of 15-20 pieces each ended up going for about $10. Most were worthless or just gold-plated, but before the auction I looked at all the jewelry and found one item that was solid 14k gold, about 3.5 grams. A few other items may have been solid gold, but I couldn't quite read the lettering and didn't want to waste my money. I asked for that one item to be auctioned separately, and bought it for $20. Now I'm reselling it for $75 on eBay. Score!
I'm going to start watching for more auctions, and bring a scale and a magnifying glass.