Aeromexico has round-trip flights from Houston (IAH) to Acapulco (ACA) for $323-$341 with a connection. Flights September to October. Extended weekends available.
Viva Aerobus and Volaris have “cheaper” fares with bag+seat fees listed on some small OTAs via Skyscanner, but we can’t verify the validity of those fares, so we aren’t recommending them. If you plan on booking there anyways, beware of any site that charges a fee to cancel a ticket within the 24-hour “free” period. Use unknown booking sites at your own risk.