For example, let’s say that, in return for a Ph.D., the hero had to give up ten years of life. I’d thought of calling that a blood price but maybe there’s a better word? Seems like maybe some Saxons or Picts would have worked some quite dramatic tradeoffs into their folklore – so, just like Irish folklore gave us the wonderful word geas, maybe there’s a short, non-Latin word for a … (substitute in for blood price) … .
How about Pyrrhic? It doesn't have an implication of necessarily great gain, but the great cost is there.
A Pyrrhic victory (/ˈpɪrɪk/) is a victory with such a devastating cost that it carries the implication that another such victory will ultimately lead to defeat.