Hi folks. If you purchase online from a site like this one (Trip Advisor or a similar site), often there are multiple sites searched. The prices are usually the same for different sites. Whatever you do, DO NOT opt to purchase from CheapOair. We figured one was as good as any other and were charged 8 times on our last purchase round trip HOU to LIM in July.
At the airport, the staff at American Airlines stated that this is not an uncommon story as well as the experiences of folks who have multiple flights but one is not included. (Example: Hou to Panama City to Lima to Quito--maybe the flight between Panama and Lima is not included--even though you paid for the entire journey and have your receipts--there is no record at the airline.)
Please, pass the word on so that others can beware.
(On a side note: There's a lotttt of cute guys in Perú. If you are a single woman, be extra aware of the risk of bringing home a wedding ring as a souviner. I met a woman in church this week that just did that--same as me. Her father isn't particularly happy. hahaha)