Geo Caching

I don't know if I spelled that correctly. In any case, are any of you involved in it at all? There was a really nice article in the local paper about it. My husband and sons are heavy into Scouting,quit smoking now, so this would be right up their alley. I am wondering if it is an easy hobby to get into. I priced some of the gps' and found one that is affordable for a beginner. My husband NEVER spends any money on himself so I would like to get this for him for fathers day. Other than the cost of the gps,quit smoking, are there other expenses involved? Thanks, Amy