If you're looking to join a local gym in Tampa Bay, you'll find a ton of options at your disposal. It is best to re-evaluate what you're looking for in a gym before you end up joining a gym that's too expensive and doesn't fit your needs.
If you're just looking for access to gym equipment, you can join a gym that offers just that for around $10 a month. YouFit and Crunch gyms offer such memberships that only offer no frills access to cardio machines and weights. Sometimes this is just enough.
If you're looking for both classes and access to gym equipment, you should turn your attention to traditional gyms like Shapes and some of the LA Fitnesses in Tampa. You'll have access to showers and lockers, too. Memberships range from $20 to $30. If you're planning on attending several classes a month, this is a good bet.
There's a breed of gyms that stand above the rest. For $40 or more a month, you'll get all of the perks of traditional gyms and you won't have to remember your towel or soap for the shower. The high cost isn't for everyone, though the higher cost may make for easier access to machines.
Open Air Gyms/Non-Traditional
Boot camp style gyms are abundant. These widely range in price and offerings. Try to sample a class before committing.