Benitez, who fought off the millionares of Chelsea to capture the goalkeeper, told of his delight in bringing Carson to Anfield.
"Perhaps it is a good message for the future," he said.
"If you want to play for a big club it's not all about money. It's important that you have a clear idea about the future and about what you want to achieve.
"It must be difficult when you see a lot of money on offer elsewhere but Scott said always to his agent that he preferred to join Liverpool. He wanted to join a big club with history and a very good atmosphere.
"I'm very delighted to have signed Scott. We've been looking at the player for a few months and we know he is a very good goalkeeper. He is one for the future and we hope to work well with him.
"We had two very good goalkeepers here already and now we have three. Scott is a lot younger but he will safeguard our future."