Sweet 12 weeks old Boxer puppy

I need to find a new home for my boxer puppy. We recently had to relocate to an apartment where pets are not permitted. He is 12 weeks old, has all of his vaccinations, and is mostly housebroken. To ensure that he goes to a good home, I am asking for a $300 rehoming fee. He is a sweet puppy who enjoys playing with children and other animals.