Buying pepper spray in new york city?

[shipley]

So after research, I found out that it IS legal here, and that I could go to a drug store pharmacy.
But I also hear that you need to be 18 or older. I'm 17. I don't want to ask my mom, because she might think I'm doing something dangerous or something. But I go to manhattan for school every day, and return really late sometimes, and having one would make me feel better.
So.
Can I just go over to the Rite-aid or CVS near my house and buy one just like that? Or do they ask for ID?
Also, how much do they cost? I can't afford it if they're too expensive.