Answer: First of all I would talk with your grandson and see if he is interested in collecting anything. I have found that the world is divided into two classes of people: those who are collectors and those who are not. If your grandson does not enjoy collecting anything, it is probably a waste of time and effort to buy him coins. On the other hand, if he likes stamps, finds different types of birds interesting to observe, and has a good measure of intellectual curiosity, numismatics is a natural.
A good first step would be to acquire a copy of A Guide Book of United States Coins and send it to him. Rather than overwhelm him with too much at once, get some feedback on what he thinks of it. If he finds it interesting, perhaps visit the U.S. Mint website and buy a modern Proof set and some other available coins. Then order three Whitman titles: The 100 Greatest American Coins, The 100 Greatest American Medals and Tokens and The 100 Greatest American Currency Notes. Each of these books is filled with interesting reading material, and the second two titles include many items that are inexpensive and affordable. Perhaps next on the list would be to buy him an MS-63 or MS-64 Morgan dollar of 1882-CC, 1883-CC, or 1884-CC and suggest that he do some reading about the Carson City Mint.
At this time I would stop and take stock and see what his interest is. If he wants you to do the buying without his advice, perhaps a good way to continue forward would be to form a 20th century type set of copper, nickel, silver and gold, starting with the least expensive varieties. Probably for some of the more expensive pieces grades such as MS-63 and MS-64 would be fine. For ones of the late 20th century, MS-65 would be the order of the day.
If your grandson’s interest continues and the lamp of numismatics is burning brightly, you are on your way.