Do i have to rebuy iphone ringtones?

Hi, so i just bought a ringtone for the first time! I actually wanted to buy another one though. If I buy another will it like erase the first one and then I'd have to rebuy it? Or would they both still be there in the ringtone settings part and i'd be able to change them back and forth anytime?

No, they will be saved in your iTunes Store forever as long as you have your account. They will be under Library, ringtones. Above where music and playlist are.

No. Anything you buy wouldn't replace the previous. Accessible whenever.