What do you mean? Your question was "What would you sacrifice for a superpower?" not "What would you sacrifice for what superpower?" So in what way is "Bodyparts or humans" not a specific answer to "What would you sacrifice?"
Unless you want to know who I'd sacrifice or what the sacrifice is for, in which case an eye for wisdom (norse mythology or any kind of seer myth ever), arms for strenght or the ability to hold onto something important, legs for movement or the ability to move forward (or both for alchemy like a certain red dwarf). Sacrificing people has a longstanding tradition in the demonic niche of wish-granting, so it's even broader depending on the kind of setup or even time, place or occasion...
Edit: This sounds more angery than intended, I'm actually just curious. ^^"