Well you cant.
You get it from Bucky Lucas. Use "pizza delivery" to get in his room.
Bucky Lucas
On Reality Island , From Bucky Lucas
talk to Bucky Lucas
you can't
bucky lucas is in room 4b at the hotel but you have to get the pizza first so you can get there
talk to bucky lucas (after you gave him the pizza)
put it on the entry form
Bucky Lucas is in room 4-B at the motel. You have to order a pizza to his room for him to answer the door.
You don't.
you go to the mailbox click the application in your inventory and then click the stamp
To get the Bucky Lucas stamp, go to the hotel entrance and use the telephone to dial the number 555-7383. Then deliver it to room 4B. Once you give the pizza to Bucky Lucas, he'll give you a stamp.