um, bare minimum for a tang, even going by a very modest estimate, is a four foot tank, and I can hear the people ready to correct me and say six feet long is the minimum (I think that kind of depends on aquascaping and a few other factors, but since I actually am not planning to keep a yellow tang until at the least I have a 200 gallon tank, it's kind of irrelevant). I strongly doubt it's a four foot long 14 gallon.
Just back slowly away from the tang, or alternatively spend about the same money on craigslist as you would for a new biocube 14 and find yourself a seventy five gallon tank with other parts and have a good time! I mean, do you really need that couch?
It just struck me. I actually paid less for my seventy than for a biocube 14 costs new. I want one so bad, but geesh they're expensive.