Here are the detailed requirements to get a Twitter Blue Checkmark:
Your account must meet the following criteria to receive or retain the blue checkmark:
Complete: Your account must have a display name and profile photo
Active use: Your account must be active in the past 30 days to subscribe to Twitter Blue
Security: Your account must be older than 30 days upon subscription and have a confirmed phone number
Non-Deceptive:
Your account must have no recent changes to your profile photo, display name, or username (@handle)
Your account must have no signs of being misleading or deceptive
Your account must have no signs of engaging in platform manipulation and spam
In other words, you just need to have a normal account for more than a month and pay $8. Verification takes about 7 days.
The case is different when it comes to the gold checkmark.
I think you should correct your advert, because a lot of people can be confused that for service that cost $8 you want to charge $999.