First off, Boot Camp is Marines and Navy, secondly, Basic Training/Boot Camp is not hard, regardless of branch.
As for saving your money, yes, it is just like a civilian job, the only different is if you get a dishonorable discharge you will forfeit all pay you ever owned, paying off Uncle Sam.
Military life is great all around, nice community on base, family friendly, and so on.
Each branch has it's ups and downs as well, Marines is a little more hardcore but has the best travel opportunities, Air Force is a little strict in deployment but offers the best Base Environment, Army is a little low on the Base Extravagance part but it's community is large and friendly. Navy is stationed on ships a lot but offers some interesting opportunities that make the Marines travel look dwarfed.
It's all about what you want, the last thing you need to worry about is if it is too hard, those who join the military have a huge advantage over some random high school grad going to college, just live life to it's fullest, don't listen to family telling you don't go or friends calling you crazy.
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The Marines and Air Force have been adapting each others training the past year, Air Force increased its Physical Standards to the Marines and the Marines increased their Educational Standards to the Air Force.
The Marines are still the top in physical and Air Force top in education, so they even each other out in the "Who's Harder" category.
