Cheapest engine for 2009 ford S-Max Petrol

Ford
Model 1-06-10 2000cc Engine Code: AOWA 4 CYLINDER INLINE 16 VALVE
Engine Code: AOWA Next Step
Ford
Model 2- 06-10 2000cc Engine Code:AOWB PFi 4 CYLINDER INLINE 16 VALVE
Engine Code: AOWB Next Step
Ford
Model 3- 06-10 2000cc Engine Code:TBWA FFV 4 CYLINDER INLINE 16 VALVE
Engine Code: TBWA Next Step
Ford
Model 4- 06-10 2000cc Engine Code:TBWB FFV 4 CYLINDER INLINE 16 VALVE
Engine Code: TBWB Next Step