You cannot expect to buy just any coin and have people begging to take it off your hands at a tidy profit for you. You need to watch out for fake coins, it is all too easy to be taken in and purchase a counterfeit coin. It is always wise to be up on your coin grading skills before purchasing any expensive coins you want to sell and always be aware of the market as it can rise and fall faster than you may realize.
Anything you invest your money into will have some risk involved. Coin collecting can be a fulfilling and rewarding hobby but if you want to make a profit from your coin buying you need to be prepared for this risk. Make sure you do enough research on the coin you are considering. If you do not have enough knowledge please seek the advice of a coin collecting professional before sinking a bunch of money in something. You can buy a fake coin all too easily if you do not have the proper knowledge.
Counterfeit coins that have been altered are not uncommon. Even the pros with many years experience can sometimes be fooled by some of the better counterfeits. Less than honest people may alter a common coin by adding a mintmark and make it look real to boot. If the coin has been certified by one of the major graders this should go a long ways in easing your mind. In the absence of a professional make sure you have enough knowledge to accurately judge the coin.
The value of a coin is often marked with a certain grade. You must know if this grade is correct. Things like whether the coin has been cleaned and how much wear it has will affect the grade of the coin. Remember whatever grade the coin has been assigned is just an opinion. Sometimes the graders do not always agree on everything so go with someone you respect and trust.
The coin market is no more stable than the stock market in many ways. You can buy a coin and have the value fall by the time you get ready to sell. This means you have the chance for big time gains or big time losses.
You may want to buy the coins you have been wanting and hold on to them for a while and when you get ready to sell them they might be worth more than you paid for them. Investing in coins could finance your coin collecting hobby if you do things right.