I'm new and want to start playing Grand Chase, but I can't seem to download it from Stove. Does anyone have any idea what the problem might be? Also, which character should I start with?

Im downloading grand chase classic on steam right now, i want to know if i can clear the whole game and doing end game content without spending any money, is it pay 2 win? I wont do PvP. What are some things i should know before and after starting to play?