[rotorwrench]

A person could re-arch the springs if they are in decent condition. Leaning cars generally have a bit more fatigue on the one side. If it still leans after arching then either bend the arches a bit tighter on the one side or replace the springs. As was mentioned, some springs can be turned around to put the driver weight on the opposite side.

Put some ballast on the other side or have someone stand on there and see how much weight balances the car out. More modern cars with dual springs generally hold up better than the buggy spring set up but good quality springs generally last a long time without problems like this.