Nobody said that you need to mandatorily pay 50 bitcoins. It's just one of the options.
The other option, as others have already mentioned, is to PM theymos which is the "free" option.
Although it's completely theymos' choice whether to accept your request or not.
May be you need to prove whether you are worthy of the name change.
The Sceptical Chymist was definitely worthy of it and got the request approved and you can try your luck too.