Getting to the Price Counter is a bit complicated but once you get there you have to escape from the Security Office and get to Freddy which is also quite complicated.
Escape Prize Counter to Find Freddy – FNAFSB Use the Prize Counter Elevator
When you finally get to the Security Office and pick up the security badge the alarm will go off and the doors will open and Monty and Roxy will look for you.
Here you need to hide until the alarm goes off. To do this successfully you need to kneel and stand next to the wall where the safe station is located.
Monty and Roxy will not be able to see you here. If you want to open or close the door you have to peek between the two buttons.
When the alarm finally goes off, exit the Office Security and head to the red door on the top left of the office. Be careful as Monty and Roxy will still be looking for you.
When you go through the red door you will have a large area in front of you. Beware of Roxy here. Here in Price Counter, next to the basketball bin on the opposite side of the room is the Gift.
Then check out Monty and Roxy on camera. Then enter the room with a white glass dome. Enter a door on the other side of the glass dome and you will encounter a sliding door.
Enter this door and continue through the hallway which glows in white and black. When you go out into the big room Roxy will block your way here.
Then head to the main menu and here is the elevator. That will complete the mission.