Tuition fees discourage many clever students in state schools from applying to go to university, a survey suggests.
It was carried out by Target 10,000, a new campaign to improve disadvantaged youngsters' access to higher education.
The survey of more than 7,000 sixth- formers also suggested that the vast majority were ignorant about the financial support arrangements.
The government says it has been tackling this, as it brings in higher tuition fees in English universities.
Although fees in most institutions will almost treble - to £3,000 a year - there are grants and bursaries for the poorest.
And nobody will have to pay the fees until they have graduated and started earning.
But, of the 7,277 teenagers throughout the UK surveyed for the campaign, just over a quarter (27%) said tuition fees made it less likely they would go to university.
Target 10,000's main practical effort is a series of free events in the summer - piloted last year - which put youngsters in touch with employers and universities who can offer advice.
They then form an information exchange network.
The survey was conducted among those signing up between April and June for this summer's events, in London, Newcastle, Leicester, Exeter, Leeds, Sussex and Manchester.
All are predicted to get the equivalent of BBB or higher grades at A-level.
Some 42% were in receipt of means-tested education maintenance allowances or income support.
More than half do not have a parent or guardian who went to university.
Almost all (95%) said they knew little or nothing about the financial support available.
Closing the gap
Co-founder Marc Zao-Sanders, said: "There are still too many bright students who are missing out on the university experience because they don't realise their claim to a place is as strong as it is.
"Students often lack confidence because they do not have access to the right information about basic issues such as financial support or even the opportunity to find out what university is all about."
He said one of the main reasons state school students were under-represented in universities was that they did not apply.
"Target 10,000 aims to change this mindset, close the gap between talent and aspiration and help them fulfil their potential."
The government - aware of confusion over its changes to student financing - has run a publicity campaign on the issue.
Higher Education Minister Bill Rammell said an independent evaluation of this, involving interviews with more than 600 students and parents, showed most knew "upfront" fees were being abolished.
"The actual application figures for the new system show that there has been no reduction in the proportion of applicants coming from lower socio economic groups," he said.
"We recognise however that with any new policy, we have to work hard to get the message across, which is why we will continue our campaign well into the new academic year as the new student finance arrangements come into operation for the first time."