Marlowe was the recipient of a scholarship set up through the will of the Archbishop Matthew Parker. The scholarship was able to pay for his schooling, and allowed him entrance into the King's School, even though he was of middle-class stock. Nothing is really known about Marlowe's life before coming to The King's School, but based on the nature of the scholarship it was probably awarded to him based on academic merit. Additionally, at least with the Parker Scholarship (students who were awarded this scholarship were known as Parker Scholars), it would have been open to anyone who met the scholarly requirements.

Source: Marlowe, Christopher. Doctor Faustus. Edited by Michael Keefer. Peterborough: Broadview Editions, 2007.