Have the grades of any coins you buy checked by an independent source. If you use a grading certificate as a second opinion, be sure you understand what the certificate represents. Grading is not an exact science, and a certificate represents only the opinion of the certification service. Find out if the certification service is, indeed, independent of the dealer and what grading standards are used. Remember that, because standards vary, coins certified by different services will be worth more or less than other coins of the same grade.
Weekly periodicals list prices for coins that have been certified by various services.
Check the prices for those coins you are considering. Exercise caution in using a financial planner for coin investments. Most are not subject to regulation or any training requirement. Should you rely on the advice of a financial planner and later discover that your coins are overgraded or overpriced, you have little possibility of recovering your funds. You may also have to pay the financial planner a commission.