yes you have to pay for the Transfer fee
here the Character Bazaar Rules:
The last Point of Point D
D. Purchasing and sales
Down-payment plans are not supported by CCP Customer Support. As a seller, you are agreeing to a certain amount of ISK only, which is to be paid in one payment. Once again, any forms of scams regarding character sales are strictly prohibited.
Agreements on the forums or in game, or winning an auction does not guarantee a character will be transferred to you. The seller may choose to renege on a deal at any time, prior to the transaction being completed.
Whenever a character is transferred before the seller has moved the ISK received from the sale to another one of their characters, the Customer Support team will return that ISK to the rightful owner. The buyer cannot expect to receive both the character and the ISK that they paid to purchase it.
The ISK that a buyer sends when attempting to purchase a character is considered to belong to him until such a time as the character being purchased has been delivered to the account of his choosing. If the character sale is not completed, the ISK must be returned in full to the potential buyer.
Customer Support will not remove bounties placed on characters either as part of a sale, or after they’ve been transferred to a new owner.
The owner of the character being sold is responsible for paying CCP the character transfer fee.