What happens to a username after the account is deleted?

Instagram: the owner may sign up again with the name

Instagram says that after deletion you can sign up again with the same username or add it to another profile, as long as it has not been taken by a new person. If a profile was removed for violating Community Standards, you may not be able to.

Instagram describes a 30 day and 90 day window for content

Instagram says deleted content is permanently removed after 30 days and that the process can take up to 90. The text does not describe when a username opens to others.

Snapchat: 30 days to reactivate, then permanent deletion

Snapchat says a deleted account is deactivated for 30 days and can be reactivated in that time, and is permanently deleted after 30 more days. In India the second period is 180 days.

TikTok: 30 days, then erased permanently

TikTok says that when you delete an account it is deactivated for 30 days and then erased permanently. Deactivating on its own keeps your data. TikTok gives no schedule for when the username opens to others.

Treat any promised release date as a guess

A seller who names a date for a username has no source. Try the name in your settings, and read which usernames can be claimed.