Hiking is great. Swimming (assuming you live near a safe body of water) can be very cheap. Simple sports like basketball and soccer are popular globally because you need basically anything round that bounces a bit and can play or practice some variant.
I think overall, any sport or activity can be expensive if you buy the bullshit that x equipment or y must have variant is the best and will increase your enjoyment. Videogames can be crazy cheap and simple considering entertainment time vs. cost but you need to be somewhat aware of the model you are playing in…and basically know how to download good stuff. Cooking can be expensive if you’re trying to emulate bullshit social apps that tell you to follow this expensive trend or you have to eat a certain food this way, but I think learning to cook and prepare in your price range is incredibly satisfying. Spend the same but it’s massively improved quality.
Reading and learning is often free through libraries and provides many benefits.