[09/04/2019 @ 3:43 PM CT] Deal looks dead. If it goes back online, we will put up another post.
Delta, Air France, and KLM have round-trip flights from Houston (IAH) to Barcelona or Madrid (BCN/MAD) for $487-$512 with a connection. Flights October to March.
Note: Carry-on bag is allowed for free on Delta, Air France, and KLM. You can avoid paying for seat selection by accepting the randomly assigned seat at the gate.