Here’s my Spanish experience. I do understand the rapid fire spanish from TV as well. Well, I did before I started learning German, but I’m working on gettin it back.
I lived in Valencia Spain. It was very cheap. My appartment cost around 160 Euros a month. Everything else was also cheaper than in the US including food. Basically, all of the necessary essentials of daily life are cheaper in Spain.
If you really wanna learn how to speak spanish in the shortest time possible, you have to make spanish-speaking friends who speak little english. This isn’t so likely in Latin America with the more educated group, but it is common in Spain to encounter highly educated people with worse english. This is no knock to the Spanish, but English is harder for them than other languages, and in Spain they don’t have the pressure to learn English like they do in South America.
But you gotta make good friends with spanish-speaking people. That’s why I would recomend Argentina, beacause you are more likely to have something in common with argentians than with the people in poorer parts of latin america.