How to Purchase Spanish Dubbed TV Shows / Movies

I was interested in purchasing/watching American movies/TV dubbed in Spanish as another way to immerse myself in the language. I know it's ideal to watch Spanish shows/movies made in the native country, but I've had limited success finding ones I like plus I know what American shows I like.

I've had some good results with newer movies on Blu-ray coming with dubbed versions, but not TV shows. Streaming isn't good. Netflix is better than HBO, Hulu, and Amazon Prime, but still very limiting.

So, how do I buy individual shows? For example, I *know* Grey's Anatomy (or Anatomia de Grey) is dubbed in Spain and available for purchase for Spanish buying/viewing/listening, yet I cannot figure out for the life of me how to buy it legally from a US address/computer.

Surely there are enough Spanish-speaking Americans that these dubbed TV shows are available somewhere.... right??

Thanks in advance!