Bugeja always wanted one of those Wells Fargo hoard gold coins, slabbed in an old green PCGS holder in a high grade. He finally got one, and a lesson to share.

A consigner-slabbed coin labeled at a much higher grade and price than the market recognizes can fool, disappoint and destroy interest in collecting.

What, specifically, does it take to win a worthwhile uncertified coin in online auctions? Some ingredients are a seller you trust, good photos, and research.

Whenever you see the same initials or user ID in bidding placed alongside your bids, you should be wary. Shill bidding—legal or illegal—may be occurring.

Private online coin auction seller Brad Lisembee writes expert descriptions and includes quality photos. A visit to his sales is a lesson in grading.

Slab labels have errors and varieties just like coins. This label's error might add value to a piece that otherwise draws a yawn from the current market.