Go to Bruski's Scrapyard. Break into the random car located near the car crusher. You do not need to pick the lock because there are no police nearby. Drive the car into the car crusher, then crush it to get approximately $400. Enter the car you came in and drive it out of the scrap yard through the north exit. Continue on this road until you drive under a bridge. Then, turn around and return to the scrap yard. Another random car will have respawned near the car crusher. Repeat the process as many times as desired. This will also unlock "Proper Scrapper" achievement or trophy easily.