I booked two round-trip flights through Trivago. Having not used the site before, I called to confirm with American Airlines that my flight was showing up in their system; it was.
The very next day, a rude man who spoke very poor English called me to explain that the discounted price I booked at had expired and that additional money (hundreds of dollars) was due in order to prevent cancellation. I refused and they cancelled the reservation.
Some additional research into this Trivago partner showed a large contingent of other Trivago costumers that experience the exact seem thing. Trivago should be held accountable for deals they advertise through their website. I will be publisizing my awful experience dealing with this clear scam until I receive some sort of resolution.