He is talking about being a donator in order to change your username.
I changed my user name - and it cost me nothing (just a request to @theymos).
@theymos is a good guy but it does not mean he would change the usernames for random newbies, so consider yourselves a part of old guard

Here is what the staff member Eal F. Skillz has to say about whether it's possible to have your username changed.
I don't think theymos have time for this anymore. Just create a new account if you don't like this username or be a donator.
PM theymos and ask him very nicely.
The forum is too big for this now. Staff, donators, and VIP can do it... so my suggestion is donate 10 BTC or create a new account.
Contact theymos he will change it for you.
No he won't, stop bothering the admin with rubbish like this or are you just posting for the sake of your prime dice payouts?
OP, name changes are only available to donators, vip and staff members.
Here's what the administrator BadBear has to say about getting theymos to change a username.
Just make the new account, nobody cares if you have more than one. Go nuts.
I agree with rpietila, theymos might do an old timer a favor and change his name, but his time is too limited to do it for the rest of us.