From what I've learned so far (I'm pretty new myself), how much you get for an upvote depends on a few different factors.

-) The Steempower of the user that votes you - the higher the more the upvote will be worth
-) How much weight the user puts into his vote. When a user has over 500 Steempower he gets a slider when he votes to adjust how much voting power he wants to spend.