Help me out /uma/, I dogeza for you

I have 19.5k carats
>14*150 in free rolls = 2.1k
>15*150 login bonus = 2.25k
>4 start up bonuses = 0.6k
>21*30 dailies = 0.63k
I'll have 24k worth of rolls, how do I get 6k carats for the pity timer? I've done vault and gotten a lot of race trophies. Should I buy a monthly pass?