Is better dun use the 2nd hand stuff for tear and wear part such like headlamp, brake disc, pad etc..especially the headlamp coz headlamp is like the soul of the car..how come u need to use the 2nd hand part??
Interior part like trim, cup holder etc is ok la..u can try to look in halfcut shop.
Headlamp = SGD840, Rear lamp = SGD530 from Hella. (For one pair)