There is no entry fee per se. For regular Tour events, all the Top 125 players can enter free of charge. They simply have to notify the particular event organizers. If you are 'fully exempt' you get a lot of freebies. I don't know if they even have to pay to get into the US Open or British Open. Certainly not The Master's, which is invite only.
I thought, based on the post, that even if you qualified you had to pay. I hear the newbies talking about sponsors and thought that they helped with entry fees. I don't know how much it would take to get started. MAybe sponsors pay for living expenses while one is trying to qualify and earn a payday.