Here is everything you need to know about the clone service:
You won’t be transferring toons anywhere. On prepatch day ALL of your toons will be copied to both TBC and Classic era servers. You have to log in to the specific era server you want your toon to be activated on. If you activate your hunter on Classic Era it will make your hunter on TBC become inactive. You can then only play your hunter on TBC if you pay 35$. That’s 35$ per toon btw.