Answer: Well admission means to enter, so in this case "admission" is being used as " I had to pay to get in/enter." So when someone says " I've seen a lot of people like you but before, I had to pay admission." they mean that they had to get pay to see certain peolple. Alougth, since they said "before" so now they are probably important now so they can see that certain person without having to pay.
For example: Going to a comic-con you have to pay to see the famous people there.