Most gyms definitely do day passes, and yeah, renting gear is standard - you won't need to buy anything upfront. The rental shoes and harnesses are pretty solid at decent facilities, so don't stress about that part. Just show up, pay for the day pass, grab what you need, and climb. It's way less intimidating than committing to a full membership before you even know if you'll stick with it.
One thing worth checking though - some places cap how many day passes you can do before they nudge you toward membership. Nothing shady, just their business model. So if you're planning to go multiple times a month, ask about that when you call. A few gyms also do intro classes included with the day pass, which honestly makes a difference when you're learning proper technique and safety stuff for the first time.