I have a few questions, how should I build Aquaman? Should I spend $50 on Shazam 3 Stars? And if not who should I for my third character for my team?

I been playing for a little over 2 months now. And have almost an incredible team, just need a great third character. So good I beat Solo Raid stage 1 in the first day. I don’t have BWTD or Shazam, I have almost half everyone and only 2 Purple characters, BMAK and Raven.