Every night at Arch 14 has two or three door prices, and they step up as the night goes on (sample).
The early price is there to fill the room for the warm-up. A warm-up DJ playing to twenty people is a different night from one playing to two hundred, and the people who come early make the peak hour better for everyone.
If you are on the guest list, entry is free until the first price step. After last entry the door is exit only.