Trying to unlock baze

I feel your pain, I never bought any shards when he was in the store, too. I finally 3*'d the node by borrowing a friend's Old Ben and using zeta Qui-Gon as my leader, so I had guaranteed dodges that would give 20% TM and boosted speed from the combination of leader abilities. Even then, I only finished Baze's 7th star a month ago, and I was farming him every day since he entered that node.

I'll say this, though--a friend of mine is 100% free to play (he spent all his money on Marvel Puzzle Quest, lol) and just finished off Baze without even unlocking his node. Instead he just bought Baze shards for crystals any time they showed up in the Shipments and he had enough to do it. So it's 100% possible to get him free if you choose to allocate your crystals to him--although doing that AND farming the node will probably be the least painful way of doing it.

Good luck!