Pet Trades can have up to 5 pets on them and you can offer up to 5 pets on other people's trades. Trading currency for pets is not allowed - you can only trade pets for other pets. If you only want to send a pet to another player, you should use the Pet Exchange. You can also buy and sell basic pets at the Pet Auctions. The trading fee is how much the trade will cost. This MP is a fee for completing the trade safely, and is not given to the owner of the pet you are trading with. The cost per pet is the same as the Pet Exchange & Auctions.