This is a newbie question for sure. When playing the DCC it has:

Forced: When this unit enters play, search the top five cards of your deck for a support card with cost 2 or lower and put into this zone, if able. Then shuffle your deck.

Does the "if able" mean you have to pay the resources to put the support card into play?

No you don't pay the costs. It is referring to being able to legally play it into the same zone as the DCC. If you played the Cannon Crew into the battlefield, and the support card you found says "Kingdom zone only" then you wouldn't be able to play it.