I love these games for nostalgic reasons but hated that they wanted $20 for an old ass game. That is until i started playing the free final fantasy app. $20 gets you practically nothing on the free app. Only 5 star characters are useful and are good enough to beat the harder content. Rolling for a 5 star is about 1 in a hundred odds. And for $139.99 You can get 32 rolls. It's insane. But now $20 for for an old ff game doesn't seem too bad lol.
I forgot to mention the old ones aren't free. I hate the new "freemium" model where they get you to pay for in game content. The old ones have a price, but you can get many hours of enjoyment from them.
My favorites are 3, 5, and Final Fantasy Dimensions. Dimentions is a newer game made in the old style like the earlier ones.