There is no maximum income level to be eligible for financial assistance. Your need for financial assistance is determined by many different factors, such as the number of people in your family and how many of those people are in college. Additionally, there are many different financial assistance programs to assist students at all income levels. The best way to find out what you might qualify for is to complete the FAFSA.
You can also use the federal Department of Education's FAFSA4caster to get a head start on determining your eligibility.