The cost of a college education has only been rising, and at some US schools, the annual sticker price now surpasses $100,000.As millions of Americans drown in student debt, some schools have implemented policies to help students better afford higher education, including free-tuition initiatives.The financial aid landscape in the US is often complicated, riddled with ultra-specific jargon, and can look entirely different from family to family. In many cases, "tuition-free" does not mean the entire cost of college is covered, and students may still be responsible for housing, food, books, fees, health insurance, travel, or personal expenses.Some of these schools are elite institutions ranking among the hardest schools to get into in the US, while others are designated work colleges offering free tuition in exchange for students working on-campus jobs.While many of these schools advertise free tuition or need-based financial-aid packages, the reality is that the cost of attendance can vary between families and depend on factors such as income, household size, state residency, and whether (and how) assets like home equity or investment funds are considered.Often, universities have financial aid calculators on their website where prospective students and families can estimate the net cost of attendance that would apply to their financial situation.Business Insider examined the financial aid offerings of colleges across the US and identified schools that advertise a free-tuition model for at least some students. For each school, we included the eligibility criteria, including the family income threshold, and what costs are covered.While this list may not be exhaustive, as many smaller schools offer financial aid packages that could cover full tuition costs, this selection indicates where some students may have a path for debt-free higher education. We also excluded the five US military academies, where cadets attend tuition-free, with room and board, as they typically entail a service obligation after graduation.These 40 US colleges and university systems offer tuition-free education paths for at least some students, though eligibility may depend on income, residency, work requirements, tribal affiliation, or field of study.