Justin Bieber treated pal Lil Za to dinner at Flavor of India Wednesday night and X17online got the exclusive shots of the bad boys' new half a million-dollar Rolls Royce Phantom!

The Biebs is growing up and stepping up the swag factor with a $500K grown-up car. Looks like he's left behind the hot box-mobile and traded it in for this lovely ride ... and we don't see Lil Za complaining!

That's not the only expensive purchase Justin's made lately ... check out the bling around his neck! Apparently being pop royalty afford you the equivalent of the palace jewels 'cause this boy just bought three over-the-top gold necklaces with rubies, diamonds and a sapphire. Bet that cost a pretty penny ...

Despite having all the money in the world, Bieber brought home doggy bags from the Beverly Hills restaurant. Waste not, want not! #munchies