I could never go to a Corolla, Camry, or any sort of mass market transportation appliance.
While I would not enjoy it as much as my BMW, I would be decently happy with something like a WRX, GTi, Focus ST, BRZ/FR-S, etc. No way I can compromise on fun to drive but the luxury trappings could be sacrificed for affordability.
Edit: not sure why I would ever need to do that though. If I needed to sell the E90 I would buy another E46, do some preventative maintenance and drive it until the wheels fell off. As long as you stay on top of maintenance and are willing to do some work then BMWs aren't much more to maintain than any other car.