I broke my tibia while bouldering, so be careful and warm up before you go.

Lots of gyms have need-based discounts, or will hire you to work, like, 2 shifts per month in return for a free membership. If you already have friends at the gym, they can often give you a guest pass. And some gyms give out free days for meetup groups, or classes that happen at the gym.

Unfortunately, more and more we are in the age of the corporate climbing gym, where they jack up prices but brag about "diversity". The grungy old gyms where a lot of the real community building in climbing happened are slowly fading away.