Green Cheek Conjure or Cocktail?

Well, unfortunately, as a general rule, both birds will cost more than 40$. If you can put about 300-600$ in to begin with (300 for the cockatiel, 600 for the conure), then you'll end up with a monthly upkeep of around 40-60$ (depending on how well you take care of the bird, of course). As your first bird, I WOULDN'T highly recommend a conure, but hey, if you've got the money and the time, then go for it. But IF I were you, I'd go with the cockatiel.