Q: Perhaps you can explain this anomaly to me: I wanted to buy a ticket to Cali, Columbia from Boston. I was quoted a fare of $1034 roundtrip. But then I discovered that the fare from Boston to Miami was $234 round trip and then the fare from Miami to Cali was $381 roundtrip. The airline rep at Continental said I had to buy a through ticket and couldn't split the fare. Why not?
A: It's maddening and confusing, but sometimes it's cheaper to buy a "split fare" like this rather than a single through ticket. The only way you can tell is by pricing the seats separately. This is something a clever travel agent would have figured out for you. Too bad so many of them have been put out of business by the Internet. There's absolutely no reason why you can't buy two separate fares and save a bundle. Just make sure there's plenty of time to make the connection in Miami, and realize that there may be different rules for checked baggage (international rules may be more stringent than domestic). Also, should you miss your connection for whatever reason in Miami, the airline will be far less sympathetic than had you bought a single fare.