I was told that check-in baggage was included. But when I got to the airport, they sa
 

That is terrible. I once had this happen with carry-on baggage. I don't trust agents anymore; now I just check the airline's website myself. When I am booking directly with an airline online, I pay attention to the information that is clearly displayed as to what is included. I do remember that with one booking through Flightd, they had icons showing whether bags were included or not, which saved me some pain.