There are several excellent pieces of advice for new collectors: 1. Buy the book before buying the coin (already mentioned.) Of course, read and study the book 2. Examine coins of the type you're interested in that have already been professionally graded. See first hand the difference between XF-40 and XF-45, MS-63 and MS-64, etc. 3. Buy the coin, not the slab. That having been said, in about 5 years of applied work you'll be ready to buy Well, that's a bit long for most people. You're liable to lose interest before you ever get there. So start with slabbed coins, the inexpensive ones, and the ones slabbed by the better TPGs. If they are SO inexpensive that they aren't slabbed then use a grading guide, info about what to look for in cleaned coins, a reasonable pricing guide (not the Red Book) and common sense. Go slowly until you get more experience.