From Tiny Tower Wiki
The Elevator is perhaps one of the most significant features of the game, and its functions separate Tiny Tower from other tower-building games. The elevator is used to shuttle VIPs and normal Bitizens alike to various floors, granting the player bonuses for their attention and patience.
Escorting a normal Bitizen to a floor will either:
1. Give you a number of Coins twice the floor number that they want to go to. (Ex. Escorting Guy Turner to the 51st floor will give you 102 coins)
2. The Bitizen will tip you 1 Tower Bux
The elevator can be upgraded multiple times to increase its speed, something that becomes very valuable with an increasingly tall tower. The faster the elevator, the more Bitizens escorted per minute, which means more cash and more chances to find a VIP waiting in the lobby. Speed is measured in PPM, or Passengers Per Minute.
Each upgrade is subsequent, and cannot be seen until all preceding upgrades have been purchased.
|Upgrade||Name||Speed (PPM)||Cost (Tower Bux)|
|1||NB200 Commercial Lift||8||25|
|2||Insta-Lift 2000 SE||12||75|
|3||Ultra-Lift 3000 Extreme||16||125|