Parents don't pay income taxes, can i get any financial aid for college at all?

My parents are both self employed, and make roughly $50,000 a year combined, but they have not paid taxes or claimed any of their income for at least 18 years since i have been born. I am a Senior this year and i need a full ride basically to go where i want to go (Colorado in Boulder, Washington U in St. Louis, and Purdue). I have a 33 on the ACT, a 4.? something GPA, ranked 8/182, I am Student Council Treasurer, and i have lettered 8 times in 3 sports at my private high school. I am nerdy and i have tried really hard to be well prepared for college, but i am afraid that i will not be able to get the opportunity that i think i deserve because my parents don't files taxes. Does anyone have any experience with this kind of situation? Thanks!