An original toned Littleton set (make sure it's really original) can be found at a bargain online, professionally graded, and resold individually at a profit.

Some auctions deserve to be ignored. Check out four important points Michael Bugeja looks for before doing business with an online auctioneer.

Original 1950 to 1955 Proof sets, packaged in cellophane and boxes, often sport vivid toning. Beware of tampering.

Privately packaged sets can develop pretty toning in time. Bidders need to know what to look for, as nothing keeps a seller from swapping out those coins.

If you develop numismatic skills, you'll know how much to reasonably risk bidding on an uncertified coin that, when certified gem, is hard to find and pricey.

Internet bidding may seem all new, but the age-old maxim “knowledge is power” still rules, if you know and can spot unlabeled varieties that demand premiums.