Fear of getting into debt is putting many students from poor backgrounds off going to university, a report says.
A three-year degree is thought to cost £39,000 overall
Information on bursaries does not reach would-be students soon enough to affect their choices, the study for education charity the Sutton Trust suggested.
The report also said that financial considerations were strongly related to youngsters' decisions about choosing a local university and living at home.
The trust said young people needed more information about support available.
Sutton Trust chairman Sir Peter Lampl said: "This report shows there is a general ignorance, especially among poorer students, of the financial support packages on offer.
"Government, schools and colleges should take note."
Simple steps like giving youngsters better information about financial support packages before they decide whether or not to go to university could make a big impact, he added.
The findings back figures released by the Office of Fair Access to higher education, which suggest thousands of students from poorer backgrounds are not claiming bursaries to which they are entitled.
It also showed universities had under spent their bursary budgets by £19m.
Staffordshire University researchers polled 1,628 students aged 17 to 19 from 20 schools.
They found that nearly two thirds (59%) of those who had decided not to go to university said they had been "very much" or "much" influenced by the wish to avoid debts.
This was almost double the percentage of those intending to go to university who said debt avoidance had affected their decisions.
Fifty-six percent of the students considering studying in higher education were planning to go to a local university.
The researchers acknowledged that this was a higher proportion than in earlier studies, but suggested it might be due to the urban setting of the group it studied.
And socially disadvantaged students with low or medium grades were most likely to seek a university place close to home.
Students with higher grades were more likely to study further afield, particularly if they were from families with incomes of more than £35,000 a year or had university-educated parents.
The study also suggested that bursaries only made a difference if they were large - worth more than £2,000.
Students who had chosen to study locally reported that the bursaries would have had little impact because the amounts on offer were not thought enough to offset higher costs of studying away from home.
And perhaps crucially, the report said, most students made their choices about studying before they heard about bursary options.
Although most of the students surveyed understood what was meant by bursaries, less than a third had actively searched for information on financial support.
Students expecting high grades were more likely to know about bursaries, the researchers said.
But even these had a "patchy knowledge" of whether they were eligible for them at the universities to which they had applied.
The National Union of Students puts the cost of a three-year university degree, including fees, living costs and books at about £39,000.
Higher education minister Bill Rammell said the report was published at a time when applications to universities were at an all time high.
And applications from young people from lower socio-economic groups in England had risen slightly, he said.
"We have introduced an improved package of financial support for students starting this year."
He added that the way information on bursaries and financial support was made available to potential students had been improved since the study was carried out.
It is now available as part of the application process and universities have been trying hard to ensure their students are receiving all of the financial support available, he added.