All excellent points that I wish would have been explained to me when I first started. My road was a bit of a bumpy one as I really didn't know what to expect, and after a fair amount of wasted dollars and frustration, I finally started figuring it out.
I would add a couple prequel suggestions to whats been said.
1. Just get out and play. Buy your eye protection, a good pair of boots, and some sort of hydration even if its only a canteen.
2. Find out where some games are, and don't even worry about buying a "good" gun to start if funds are tight-ish or you're unsure if you will even enjoy it. Rent/borrow a gun and get out and play. At your first event both before it starts and after it ends (not during), wander around to folks and ask questions and see what gear/guns they are using. Most folks will be more than happy to give you advice and show off what they use.
3. After that, you can go home and more wisely plan what your starter budget is going to be like as you will have at least a better idea of what you like/don't like and your play-style. As already mentioned, don't be deceived, airsoft is a money pit. That starter budget is exactly that.
It may seem expensive to rent/borrow some gear for your first game, but later on you will be glad for the money saved in not buying a piece of junk or something you don't like (which is very possible if you don't do your research) or finding out you don't like air soft in the first place. (can't see why that would happen, but its possible.)