chris, the payscale's the same across the board for all of the services and all jobs. In other words, E-1 cops, cooks, aircraft mechanics, hull technicians, or whatever all get paid the same, and if there's a like job in another service, they get paid the same, too.
There's a big BUT, though. All of the services have programs that pay bonuses for people (who qualify) who sign up for specific career fields, and those fields differ by service. There's also bonuses for signing up for longer enlistments. The bonuses are not usually paid out in one lump some, but split up and paid on each anniversary date of your enlistment. A recruiter can tell you more, but bring a strong dose of skepticism and reservation with you when you talk to them.
Oh yeah, one more thing. The E-1 pay goes up after 4 months. Guess the bean-counters found a way to save some money, especially from recruits who don't finish basic training.