[2021] Cheapest way to unlock Operators?

I'm new to R6S, I only have Castle and Fuze unlocked at the moment.

What are my options in terms of unlocking Operators?

I only have about 3 hours a week to put into the game so ever earning 25,000 Reown to get one is not really an option.

I have the Standard game. What could I purchase (and how much?) to enable me a few other Operators?

Thanks in advance.....