The quests between when you hit 50 and when you get to Heavensward will give you a full set of blue ilevel 110 gear. And then the quests (and side quests) in Heavensward will give you high quality white gear of the appropriate level. If you choose it well you can get gear for both a melee and a ranged job (I leveled and geared dragoon and summoner at the same time when I went through Heavensward). Only the accessories can be tricky as they're not split. You won't need to buy any gear off the market board at all.