This trick requires two players. Start a game, and grab the magazine you
want to duplicate. Then, have player two do the same in their own game.
Have both players save the game <#>. Next, have player two join player
one's game through Co-op, drop the magazine, and then leave the game.
Have player one pick up the magazine, and save the game. Player one will
now have two copies of the magazine. You can repeat this process until
you get twelve of the same magazine. Thus, if you have 12 Bargaining
magazines, the price at pawnshops decreases 120%. If you have 12 Driving
magazines, you will basically have an indestructible SUV.