Usually go through my dive shop. It does take all the "hassle" out of the planning. They plan several trips a year and I can pick and choose among them. Another advantage is that I will usually know a few people in the group they put together, and I get to meet a few new local divers. Also, if the place sucks, it is always nicer to have people you know to help you laugh at the situation. I think they use PADI Travel or go through the resort directly. Depends where we are going. All in, it really isn`t cheaper for me to do the planning, I`ve tried.