Here are some flights I pulled up just now. I realize that the taxes add on to the fare, but you're going to pay those with any airline. It's not the airlines, it's the airport taxes, departure taxes, etc. If you look at your ticket, they actually give a breakdown of the charges.
All of these flights have only one connection through Houston or Dallas (with exception of the Houston and Dallas flights of course)
Continental, September 27 - Oct. 1 (Wednesday - Sunday)
Houston (IAH) to CZM - $303 (plus taxes)
http://www.continental.com/web/en-U...lt1.aspx?SID=2E5550CF80004CE4879BC7AAEE9DD673
Chicago (ORD) to CZM - $424 (plus taxes)
http://www.continental.com/web/en-U...lt1.aspx?SID=8380B0C2396D43BC9C387718FBCC4033
LAX to CZM - $373 (plus taxes)
http://www.continental.com/web/en-U...lt1.aspx?SID=B5E99D6399F349199CEEDAC028DB30AB
Newark (EWR) to CZM - $335 (plus taxes)
http://www.continental.com/web/en-U...lt1.aspx?SID=6190FC4A78BC4F36956DDFB5349D6677
American Airlines, September 27 - Oct. 1 (Wednesday - Sunday)
Dallas (DFW) to CZM - $481.10
https://www.aa.com/aa/reservation/e...BFFS4VMD?bookingPathStateId=1158072521438-330
LAX to CZM - $480.10
https://www.aa.com/aa/reservation/e...BFFS4VMD?bookingPathStateId=1158072437088-207
Newark (EWR) to CZM - $446.63
https://www.aa.com/aa/reservation/e...BFFS4VMD?bookingPathStateId=1158072294637-483
All of these flights have only one connection through Houston or Dallas (with exception of the Houston and Dallas flights of course)
Continental, September 27 - Oct. 1 (Wednesday - Sunday)
Houston (IAH) to CZM - $303 (plus taxes)
http://www.continental.com/web/en-U...lt1.aspx?SID=2E5550CF80004CE4879BC7AAEE9DD673
Chicago (ORD) to CZM - $424 (plus taxes)
http://www.continental.com/web/en-U...lt1.aspx?SID=8380B0C2396D43BC9C387718FBCC4033
LAX to CZM - $373 (plus taxes)
http://www.continental.com/web/en-U...lt1.aspx?SID=B5E99D6399F349199CEEDAC028DB30AB
Newark (EWR) to CZM - $335 (plus taxes)
http://www.continental.com/web/en-U...lt1.aspx?SID=6190FC4A78BC4F36956DDFB5349D6677
American Airlines, September 27 - Oct. 1 (Wednesday - Sunday)
Dallas (DFW) to CZM - $481.10
https://www.aa.com/aa/reservation/e...BFFS4VMD?bookingPathStateId=1158072521438-330
LAX to CZM - $480.10
https://www.aa.com/aa/reservation/e...BFFS4VMD?bookingPathStateId=1158072437088-207
Newark (EWR) to CZM - $446.63
https://www.aa.com/aa/reservation/e...BFFS4VMD?bookingPathStateId=1158072294637-483