Re: Dock vs. mooring
The biggest advantage to starting out on a dock with a new boat is the security of being "plugged in" to shore power, until you are absolutely certain the boat will not drain her batteries, leaving you with no bilge pumps.
If you are new to boating a slip gives you a lot of opportunities to learn how to maneuver your boat in varying conditions under power. This is something every boat owner should learn and picking up/ dropping a mooring just won't give you that education. Once you are comfortable handling your boat under power and you feel that she will stay afloat for however long you intend to leave her, no matter how much it rains, then moving out to a mooring is certainly cheaper.
IMO, it is a better place to hang out, but I might be prejudiced; we spend 11 months on our anchor through out the Antilles and one on our mooring in Honeymoon in the VI.
"Any idiot can make a boat go; it takes a sailor to stop one." Spike Africa aboard the schooner Wanderer in Sausalito, Ca. 1964.