Should the one friend always pay

If two friends want to hang out together one has money and the other doesn’t do you believe that the one with money should pay for everything? I’ve heard people say this before but why would one person have to pay for everything just to do something with a friend?

Example: the two friends want to hang out friday night at the movies then a restaurant, one friend pays for the tickets, candy, drinks, etc and the restaurant bill.

Is that okay for the friend to pay for everything or the other one to expect them to do or wrong for the friend to do or expect of the other?