The problem I have with US flights to save money is that you never know exactly how long it's going to take to cross the border, or whether you will have an unexpected problem. It could take 15 minutes, or it could take 3 hours. In practice, that means I have to take a really early bus (Vancouver to SeaTac), or go the night before and stay in an airport hotel, if it's a morning flight. With Priceline, it's not so bad to stay near SeaTac, and if I can justify it as part of the holiday or as part of an overall best deal, I don't mind.