Today’s reality: Before you decide on which college to attend, you have to come up with a way to pay for it.To that end, families are relying on financial aid more than ever before to help cover the skyrocketing cost of tuition.More than 8 in 10 families tap scholarships and grants — money that does not have to be repaid — and more than half of families borrow, or take out loans, according to the most recent report by education lender Sallie Mae.But to access any of that assistance, students must file a Free Application for Federal Student Aid form, which serves as the gateway to all federal money including loans, work-study and grants.For the 2020-2021 school year, the FAFSA filing season opens Oct. 1 — and the sooner students file, the better.Some financial aid is awarded on a first-come, first-served basis, or from programs with limited funds. The earlier families fill out the FAFSA, the better the chance to be in line for that aid, according to Ashley Boucher, a spokeswoman for Sallie Mae.If you wait, there may be less money available so your financial aid may be more loans, less grants.Mark KantrowitzSavingForCollege.com”If you wait, there may be less money available so your financial aid may be more loans, less grants,” added Mark Kantrowitz, publisher of SavingForCollege.com.As of last year, 77% of undergraduate families completed the FAFSA, up from roughly 70% a year earlier, according to Sallie Mae.Despite the rise, millions of students who would have qualified for college grants still fail to file, Kantrowitz said.High school graduates in 2017 missed out on $2.3 billion in federal grants because they didn’t fill out the FAFSA at all, according to an analysis by personal finance website NerdWallet.Among those who didn’t apply, most said it was because they didn’t think they would qualify. Others said they either didn’t know about it, missed the deadline, didn’t have the necessary information or felt the application was too complicated, the education lender found.And only 25% did so as early as October, while the majority of families waited until January or later, potentially missing out on free money for college, Boucher said.It’s a major misconception to think you won’t qualify for aid, Boucher said. “Nearly every student is eligible for some form of financial assistance, whether it be grants, work-study funds, federal student loans, or a combination.”In fact, there’s more to determining a student’s aid than income and savings, such as the school’s cost of attendance or the number of college-age siblings.More from Invest in You:What college students can do now to start investingWhat’s your smart money IQ?Here’s how to avoid some big money mistakesFor example, if your family has two children enrolled in college, “that’s like dividing the parent’s income in half,” Kantrowitz said. “That has a huge impact in aid eligibility.”Some states are taking the guesswork out of applying for aid by requiring all high school seniors to fill out a FAFSA. In addition to addressing the immediate financial need, studies show that easing the burden of paying for college pays long-term dividends.”Students that get the financial aid they need are more likely to go to college and graduate from college,” Kantrowitz said.CHECK OUT: 4 of the top money lessons a CPA learned from his CPA dad via Grow with Acorns+CNBC.Disclosure: NBCUniversal and Comcast Ventures are investors in Acorns.