There is no tuition fee for students from the United Kingdom, the European Union or the Channel Islands and the Isle of Man. All other students are required to pay tuition fees, which vary depending on the course of study. For example, the annual tuition fee for an undergraduate degree in arts or humanities is £9,250 for students from outside the UK/EU, while the annual tuition fee for an undergraduate degree in science or engineering is £11,150 for students from outside the UK/EU.
In addition to tuition fees, students at Oxford and Cambridge are also required to pay college fees, which cover the cost of living in a college, including accommodation, meals, and access to college facilities. College fees vary from college to college, but the average annual college fee is around £10,000.
So, while it is not possible to directly pay to enter Oxford or Cambridge university, students from outside the UK/EU will need to pay tuition and college fees in order to study at these prestigious universities.