Sold 5 mil out the gate and numbers do not lie
You can’t deny his popularity when his debut album, The Documentary, went 5x platinum. It actually sold 2.5 million in the U.S. which is 2x platinum under RIAA. The 5 mil' Game is referring to is the World wide sales of the album. .
Game is also quoting one of his favorite rappers, Jay Z:
To help improve the meaning of these lyrics, visit "The City" by Game (Ft. Kendrick Lamar) Lyrics and leave a comment on the lyrics box