I love my Carnival agent. I think it is much better to go through Carnival. She said that she had the very lowest prices, so if you find a cheaper price with a TA, I would go to Carnival and I am sure they would match it.
Royale 5/85; Oceanic 7/85, 5/86, 5/89
Veracruz 7/88; Fantasy 7/97;
Tropicale 6/98; Sov. Seas 6/99;
Sensation 5/03, 5/04; Glory 9/03,Triumph 9/04; Pride 3/05
I'm afraid ... in most cases, this is a misconception. There's absolutely no reason for Carnival to offer you a lower price than a travel agent... and they certainly WILL NOT lower their quoted price to match a travel agent.
Travel agents basically get the same rates as you would by calling Carnival direct. However , in that price is their commission. 90% of travel agents will discount a portion of the their commissions in order to get your business. Therefore you are getting a lower price.
If Carnival really wanted your business they could offer you a discount equal to the commisssions they pay travel agents ( anywhere from 10-18%), but they don't do that.
In fact, you can book with Carnival at the best price they offer, then shop your booking to travel agents. When you find a discounted price you're happy with, Carnival will allow you to transfer your booking to the agent, and the reduced price.
If you really believe you're getting a better deal booking direct... do what I suggested above. Lock in your reservation, and then shop it. You will save money from Carnival's price!