Let's take the example of an RN/BSN with four years of clinical experience who applies to the USAGPAN program.
(Taken from 2007 Pay Scale, to get an current number, look at current DOD pay scales by clicking here)
So you come in as a 1LT with a monthly base salary of 3,059 which is taxed so lets say .3 * 3059 = 918 and 3059 - 918 = 2141/mo plus your BAH with dependents (assuming kids) is 1257/mo and then add BAS 223/mo for a total of 3621/mo WHILE YOU ARE IN SCHOOL (plus health and dental for you and your family).
That is 43452 take home per year plus benefits WHILE YOU ARE IN SCHOOL.
Then you graduate now you are a CPT making 4330/mo and after tax roughly 3031/mo plus BAH now at 1353 plus 223/mo BAS now you are making 4607/mo as a new grad or 55284/yr take home. BUT you have no school loan debt, can moonlight on your days off (with command approval), AND get a 15K per year bonus during your 4 year payback.
So new grad CPT CRNA (with no prior military experience, because that puts more in your pocket if you do) makes roughly 70284/yr TAKE HOME, plus no debt AND if you work off-duty (given command approval) an average of 90 hr/yr (conservatively... that makes 25920/yr).
PLUS, no debt..... PLUS you have been trained to work VERY independently and WELL versed in regional techniques. So you now payback your 4 years after school. Now you are a military grad with four years experience and NO DEBT.... just imagine your marketability now.