Lots of airlines are now charging $25 to $50 to check in bags when you are flying. If you know you're going to have to check bags, one thing to consider is sending your stuff ahead of time via the post office or UPS. This is often cheaper that the fee charged by the airline. And it can be more convenient since you don't have to haul the bag around and it ends up directly at your destination. THis is especially true if you are traveling with kids and your hands will already be full.