A bubbler isn't required, if you get a betta fish. They've adapted simple lungs and will gulp air from the surface of the water. It will travel just fine in a plastic bag that is half filled with air. Dealers send fish all over the world in this manner. If you get the fish from a mom and pop pet store, I'm sure they'll show you how to close the bag there is plenty of air without using a compressor or breathing into it. While you're there, they would probably give you a few bags and rubber bands if you ask. Then, travel with the bag in the bathroom sink so it doesn't roll around. Refresh the air in the bag when you stop for gas or to eat.