M*A*S*H is not streaming on Amazon Prime Video. I repeat: M*A*S*H is not streaming on Amazon Prime Video.
You can add Amazon Prime Video to the list of places you can purchase M*A*S*H episodes as digital downloads, joining iTunes, YouTube, and Google Play. I noticed the series available for purchase sometime last month but completely forgot about it.
Like iTunes, you can purchase individual episodes from Prime Video in SD ($1.99 per episode) or HD ($2.99 per episode) as well as complete seasons in SD or HD ($19.99 per season except for Season 11, which for some reason costs $24.99). I cannot find an option to purchase the entire series.
Prime Video is supported on Amazon Fire devices, iPhones, iPads, Android devices, plus select Smart TVs, Blu-ray players, gaming consoles, streaming media players, and through some cable set-top boxes.