Sign up through the website, the Fitness Time app, or in person at a branch. At purchase, you decide whether the membership starts immediately or the following day.
Prices vary with the membership category and its length; since the FAQ page lists no fixed prices, ask at a branch or look up current rates in the app or online. To try before buying, book a free trial through the website, or have branch staff walk you around the gym's facilities ahead of paying. Fresh offers appear on the website, in the app and on their social media.
Source: Fitness Time: FAQ