Along this strips of Francisco Otaviano you'll find all the surf shops you need to get your gear. I…read morebought my first board here, a 6'8" Evolution, and paid a reasonable R$900 for it. This is definitely one of the nicer, larger, and more organized shops in the lineup and the guys working there are friendly and helpful in getting you on the right board.
While this shop is good for beginner surfers looking to pick up a board/gear, it offers a better selection for intermediate and advanced surfers. You'll find a great supply of Al Merrick, Rusty, FireWire, and other top quality boards (some are imported while others are manufactured here in Brazil).
You can also find leashes, wetsuits, fins, SUP, swimming gear, shoes, skateboards, apparel and lots of other accessories for active sports. I recommend checking this place out as you shop around.