Participating in any of the currently available Internet set registry programs costs nothing and offers lots of enjoyment at every level. That numismatists can now electronically display and share their coins with other enthusiasts brings a wonderful new dimension to the hobby. But before you get too excited about building a registry set please give some thought to these considerations:
Building the finest set of coins you can afford has always been a common goal among the collectors I've known. Satisfaction should be gained from locating and acquiring every coin you add to your collection, be it a VG or PR-69. The surest way to turn a great hobby into stressful work is to spend more than you should on your collection.
Don't abandon your current collecting interests simply to participate in a set registry program. If you're looking for a new direction, carefully study the set registry options available. The idea is to have fun, communicate with lots of great people and learn more about the hobby. My experience has been that collecting what the majority has overlooked is often a very satisfying way to go. In baseball, the way to score runs is to, "Hit it where they ain't". Being a non-conforming numismatist can provide affordable challenges and lots of fun. Please examine all the options the set registry programs have to offer.
My understanding is that current set registry programs being offered on the Internet are maintained by for-profit grading services. The venues they provide are simply wonderful and the founders should be congratulated for establishing them. One should also keep in mind that these grading services and certain coin dealers may stand to benefit financially from your participation in a set registry program. Your goal should be to have fun while adding a new element to your collecting activities. Don't be surprised if there ends up being some cost associated with your involvement.
To gain maximum enjoyment from your participation in any set registry program you must follow three simple rules. Go slow. Go slow. Go slow. A very common fault among coin collectors has always been to try to do too much to fast. In my view, the formats used in set registry programs, perhaps inadvertently, encourage participants to rush to complete sets. Certainly there are many intelligent collectors who avoid this trap and proceed cautiously while savoring the excitement and fun that should come with every acquisition. What can possibly be gained from hastily assembling a set when you know certain coins are only temporary fillers that will ultimately be replaced? My experience has been that those who rush to complete a set end up costing themselves dearly both in frustration and cash. Please investigate the various set registry programs and associated discussion forums. If properly approached, these venues can add much to your enjoyment of our great hobby.