Well, there are not ALL locked you can play with 5 classes without expending a penny, you can unlock 2 ending per class, that means you should beat the game at least 6 times (and you can do it without repeating any party combination) to unlock all the free content!
If you really loved the game and want to unlock the extra challenges and content you can do it (and it would help us to keep making games with better budget), if you dont like it that much you can still play for free and have a lot of fun :D
 "Mercenaries of War"){kind=icon}
 "The King's League: Odyssey"){kind=icon}
 "Champions Of Chaos 2"){kind=icon}
 "Raze 2"){kind=icon}
 "Strike Force Heroes 2"){kind=icon}
 "Burrito Bison"){kind=icon}
 "Legend of the Void 2"){kind=icon}
 "Cyber Chaser"){kind=icon}
 "Min Hero: Tower of Sages"){kind=icon}
Well, there are not ALL locked you can play with 5 classes without expending a penny, you can unlock 2 ending per class, that means you should beat the game at least 6 times (and you can do it without repeating any party combination) to unlock all the free content! If you really loved the game and want to unlock the extra challenges and content you can do it (and it would help us to keep making games with better budget), if you dont like it that much you can still play for free and have a lot of fun :D