If you are going to start a coin collection of your own, you will want to make sure that you have some things in order before you begin. The first thing that you need to do is make sure that you know what types of coins you are going to want to buy, and you need to make sure that you know a bit about the history of the coins. Simply buying the coins through the local coin dealer is not usually enough for a collector. They will often try to learn all about the minting, the years the coins were made, any coins from that era that might have anomalies (making them worth more) and the like. Knowledge is very important to collectors.
As a collector, you are also going to want to know the current prices for those coins in which you are so interested. This will make it much easier when you start looking for a coin dealer. If the dealers you find are charging far too much for the coins, you should find someone else. If the dealers are not charging near enough for the coins, you can be reasonably sure that the dealer is trafficking in fakes.
When you know the coins you want, their history, and their current price, you can start your search for a coin dealer. You can find coin dealers who have shops in your local area, but you will probably have a much better chance of locating the coins you need if you use the web to look for online dealers. They will usually have a larger stock of coins, and buying through the online dealers is quite easy to do.
Always choose a company that has a good reputation. If you choose a small company that no one has ever heard of and that has only been around for a short time, there is a good chance that you could be in for trouble. Even if the seller offers real coins, those small companies will usually have a shoddy shipping department or poor customer service. It's not always their fault, but small and new usually equals trouble.
Make sure that your dealer will be able to deliver the coins to your home address, and confirm the shipping date when you order. Since you are ordering valuable coins, you will want to be home when the shipment arrives.