h1b and h4 extension filing together premium processing fee

My H1b visa is expiring in 2 months. My employer recommending me to file extension in premium processing. (My employer won’t pay for premium processing). So if I file my H1b visa extension along with my dependents h4 visa together, what would be the entire fee I need to pay USCIS for filing?

no premium processing for H4, just pay H1 premium, both H1 and H4 gets approved together 99% of the times.