Most states follow something known as guideline support which takes into account income earned by each parent, amount of time spent with the child, educational expenses for the child and so forth. There is also often something known as spousal support in many states which applies if you were married that can offset the amount.
Here is how Arizona handles child support http://www.azcourts.gov/familylaw/Ar...uidelines.aspx you can plug the numbers into the calculator and see what comes up. The answer to your question is both parent's income matters they will not require someone making 50,000 a year to pay full support to someone after they won the lottery.

