How do I buy another CHANGE GAMERTAG???

You can find instructions on how to change your gamertag here - https://support.xbox.com/en-US/my-account/manage-gamertag-and-profile/change-xbox-live-gamertag

Unfortunately no. All you can do is buy another gamertag change if you want to change it to something else.

Buying someone elses account is against the terms of use so if you did don't mention it on the forums or to an official xbox representative. And it wouldn't be easily possible for them to change it because they would have to buy a gamertag change change
it to something that is different that what it is now (gamertags arn't case sensitive when making them its just how they appear) and then buy another gamertag change to change it back with the different case. idk about you but trolling someone isn't work 20
bucks.

Nope all they do is delete yournms account of private info

it doesnt free up your gamertag

the only way to free your name is to buy a gamertag change to free it

then use another change to reuse it on the new account

sorry but i don't really understand the problem here.

you lost your gamertag while unstalling your profile.

but what do you want? your old gamertag back?

well if so i'm sorry but for that you gonna have to buy a gamertag change. here is how:

How to change your gamertag on the Xbox 360 console, you can easily change your Xbox Live gamertag. If your gamertag during your first log on to Xbox Live for you is made (in other words, if you haven't chosen your gamertag), you can change this gamertag
once free. Additional changes of the Xbox Live gamertag cost extra. Your Xbox Live gamertag sign on your Xbox console with the Xbox Live gamertag that you want to change.

Go to Social, and then select your gamertag.

Select Change Gamertag.

Note the price of the change, and then do one of the following: Select Enter New Gamertag. If the gamertag entered is already in use, you will be prompted to try another gamertag.

Select Get Suggestions about possible gamertags.

After you have entered a new gamertag or chosen, select Yes, use this gamertag.

When you have your new gamertag confirms, the change is automatically anywhere on Xbox Live. You do not need to tell your friends that you have changed your gamertag: their friends lists are automatically updated.

Did you make a mistake when creating your gamertag?

If you make a mistake when creating your gamertag and you want to change it, then you need to buy a new gamertag. All purchases of gamertags must be performed using the dashboard and cost extra.