Instructions
Purchase a subscription from the U.S. Mint. Your subscription price is the cost of the silver proof sets that you want to buy. You can only order future sets, such as subscribing and paying in 2010 for the 2011 silver proof sets. According to the U.S. Mint subscription policy, "No previous releases will be included as part of any subscription."
Buy silver proof sets from a reputable coin dealer in your neighborhood. He can help you to fill in the missing years of your collection by selling coins from his stock or contacting other dealers to find the more rare silver proof sets. Additionally, you have the advantage of examining the coins before buying them.
Buy silver proof sets from the Internet sites of reputable coin dealers. A Google search will list thousands of dealers. Check the dealer's reputation with the Better Business Bureau in the state where the company does business.
Attend a coin show in your area as many of the dealers sell directly from their booths. You might snag a discount because there is so much competition under one roof. This can be an excellent learning experience if you are just starting to collect silver proof sets.