There are several types of VIPs who can appear in your elevator at random. These special guests give you bonuses that can boost your coins or make things happen more quickly.
The construction VIP wears a yellow hard hat and an orange jump suit. If you send a construction VIP to a floor that is under construction, he or she will reduce the construction time by three hours.
Big Spender VIP
The Big Spender wears sunglasses and a green outfit. If you send the big spender to a business that has items in stock, the big spender will choose a random item and buy all of what's left in stock of that item. You can get a huge amount of coins this way if you have a large number of expensive items in stock, but if you choose poorly, the big spender might buy a cheap item that only has a small number left in stock. It helps if you can remember which of your stores have the largest amount of stock and have been stocked most recently.
The celebrity VIP wears a pink outfit and sunglasses. Sending the celebrity to a store will cause a huge number of customers to visit that store for a limited time, each buying a random in-stock item. It's a good idea to send the celebrity to a floor that only has the most expensive item in stock. Be warned, though, that the customers will stop coming if that store runs out of stock.
The delivery VIP wears a dark brown jump suit. Send the delivery VIP to a business that is currently being stocked. The delivery VIP will reduce the restocking time by three hours. I recommend sending the delivery VIP to the floor that has the longest time left to restock.
Real Estate VIP
The real estate VIP wears a dark blue outfit and, if male, a red tie, or if female, red earrings. If you send the real estate VIP to an apartment that has fewer than five residents, the real estate VIP will fill that apartment with new bitizens so that it has five residents. I recommend sending the real estate VIP to an apartment that has the fewest number of residents living there.