This is an interesting one as prices for BMW 3-Series models of this age vary wildly. The 318i is a lower end model and less desirable than the six-cylinder cars, but being petrol it is ULEZ exempt and the tiny mileage is a very clear selling point. We would estimate the value to be between £5000 and £6000, approximately 50% higher than a model with average mileage. You may have to wait for the right buyer, though.