The one time fee for lifetime membership is (or always has been) $35. You can call the Captain's Club desk at 800-760-0654. We joined after our first cruise. My brother joined while on his first cruise but I don't think he got the benefits of priority debarkation on that cruise. I don't know if you can join while booking your first celebrity cruise but I'm sure thay can tell you. The priority boarding and debarkation are the main ( and very useful) benefits, Supposedly you get a category upgrade but it's only on the lower categories where they is only a $50 or so difference and at celebrity's prices which you might be able to do better elsewhere.
Other benefits, luggage tags, Celebrity Captain's Club pins, Video of your choice, Newsletters periodically, and Captain's Club reunion cruise invitations and discount coupons on other sailings. The priority embarkation and disembarkation as well as an extra cocktail party are nice perks.
Thanks for your feedback... I, too, found out that you can't join until you've sailed Celeb. at least once... That's a shame since it sounds like embarkation and disembarkation is a hassle without it (out of Baltimore).
After 7 Celebrity cruises and being a captains club member from day one., I can tell you it buys you nothing but a couple of free water down drinks. Their special pricing and advanced notice are usually a savings off the list price which only a fool pays. Yes you can get in early on the ship but beyond that it is not worth the money spent.
Celebrity should take the time to learn what hotel chains do for their frequent users and try too emulate.!