The best and easiest way to complete this achievement is to simply play the game, do as many quick races as possible (I completed all the quick races from the Hot Wheels City Rumble single player company) and, of course, ideally take prizes - better arriving first, because with it you will receive more than 500 coins, which is just enough to buy 1 box in the game store, so by gradually buying and opening the boxes you will unlock the achievement.
UPD: This guide is written for getting all the box farming achievements!
I have about 14 hours of play!
good luck everyone smile wink