One thing that is having an impact on the hobby of coin collecting is the influx of fake coins mostly from China. The Hobby Protection Act requires that all imitation or replica numismatic and political items sold or imported into the United States must be marked with the word "Copy" or the year of manufacture placed on it somewhere.
Unfortunately many of the Chinese fake coins ignore the requirements of this law. You will find nothing on these fakes and counterfeits that identify them as copies or replica coins! Most of these fake coins turn up on eBay and other online auction sites.
If you decide to bid on coins listed on eBay or a similar auction site, look for detailed pictures on the auction and don't be afraid to seek the opinion of others about any coin you are interested in bidding on.
Over Graded Slab Coins
With slabbed coins you might think you would protected from coin scams. No doubt you have read that you should buy slabbed coin rather than "raw" or un-slabbed coins. Normally this would be good advice, but you have to be aware that there are many new companies that have sub-standards for grading and slabbing coins.
These sub-standard coin graders generally over grade their coins. You will have to do your own research on the different coin grading companies.
Coin Periodical Advertisers
Buying from a coin dealer that advertises in a major coin periodical should be a safe venture you would think. This isn't always the case. Some of the coin dealers that advertise in the major coin magazines are well known for selling cleaned coins as BU/UNC coins. Before buying coins from any dealer that advertise in coin periodicals. Use your favorite search engine and do some research on the particular coin dealer in question and see what comes up.
Coins Advertised on TV
Be extremely cautious about buying coins on TV. Any coins advertised for sale on television are normally over-priced! Do not get caught up in the advertising hype. Consider how much it costs to run one of these television shows.
They don't get their coins for free any more than you will. Never forget someone has to pay for the show, and that someone is going to be anyone who buys their over-priced coins! You don't want this to be you!
Altered coins are very difficult to detect and many of these coins have been known to fool the experienced coin experts. Always buy your coins from a reputable dealer. This will minimize your chances of getting stuck with one of these doctored or altered coins. Remember some altered coins have fooled even the best coin experts and some of these coins have been certified and slabbed by some of the top tier coin grading companies.
Large Newspaper Ads
Occasionally you will see large advertisements in a newspaper placed by some company that claims to be selling the last of something or some type of rare coin. Most of these ads are made to look like a news story. If you look hard enough you may see something that states it is an advertisement, but don't be surprised if you don't see anything to that effect.
The only news for you in one of these ads is that whatever is being advertised for sale is generally junk and will NEVER rise in value. Some of this junk for sale isn't even real coinage! A little research here will go a long way in saving you money. Remember just because the ad is large, doesn't make it legitimate!
Final Words for the Wise
Doing a little research on the coins you are interested in buying and the dealer selling them will save you a ton of money in the long run. Spending $10,000 dollars on some rare coins only to find out they are fake or over-graded is going to be a very expensive lesson you don't need to experience. Don't be afraid to ask a lot of questions. After all it's your money at stake!