Probably different reasons in different situations:
POR - Jet Rink (character in "Giant" movie) calls up New England Dealer and says in a strong West Texas accent "I just hit some oil wells and would like one of those English Purdey guns and see you got one. How much is it?" Answer "$60,000"
POR - Eightbore calls up same dealer about the same gun and asks a half dozen questions and then asks the price. Answer "$21,000"
POR - Same dealer and gun. Dealer bought gun from son of deceased friend $14,000. Son calls up and asks how much. Answer "16,500"
Best,
Mike
Amarillo Mike has hit it on the head above. In addition, there are a couple other "reasons" for POR. (I don't like the reasons, but here they are)
1. When dealing with extreme high dollar investments, the potential buyer wishes to conceal the purchase price (and the seller to be discreet) with the intention of a future sale/flip of said item. If the asking price was known, it may impact the arbitrage in a future sale.
2. The dealer may ratchet the price down without embarrassment over time in the event his initial ask was too great.
3. Protect the maker. I see this a lot with Luciano Bosis shotguns. They go all day long for $25,000 at auctions but their suggested retails may be $50,000-$60,000 for the same gun. If you want to be an exclusive dealer and receive their guns in the future, you don't advertise them at fire-sale prices in a down economy, you gently ease into that number via direct negotiation with the end customer.
4. The seller may be willing to part with the item at a pretty narrow margin. It doesn't portray financial strength or a powerful negotiating position if he/she advertises a gun at what may appear to be a 5% markup.
Many reasons, all legitimately used...yet I don't particularly care for any of them. Then again, I can't stand the false notions of "the price is fixed" or "we never discount". I found those sentiments to be utter hogwash when it came to luxury goods like Rolex and Subzero, for example. They always say POR and then in person give you the "fixed MSRP". Anyone with half a grasp of negotiations never pays the non-negotiable price that was POR.