Two words: market education
Applies to sellers (owners, brokers, dealers, distributors) and buyers.
Remember, dealers and brokers are direct competitors against collectors.
Owners are not collectors by basic definition.
PinSide is not "the market" or an exclusive source of game acquistion.
Periodic inflationary periods cause problems. Manufacturers also are a source of artificial pricing increases and "scarcity", common presently.
Other people use different sets of two words to describe what I am referring.
Supply and demand, greed and profit, fad and interest, enthusiasm and common sense, or logic and knowledge. Some are more accurate descriptions than others.
There is nothing wrong with paying a premium for a fully restored quality game.
It is completely wrong when an unscrupulous seller tries to unload a steaming turd with missing parts, blown electronics, and poor cosmetics onto an inexperienced buyer during a period when the market 'tidal wave' is high.
The experience comes from knowing the difference between the two, which requires the knowledge and wisdom gained from others in this hobby, time and experience, and using network contacts.
An well versed collector can locate and acquire nearly anything except the most rare of collectible items directly, just like a big game hunter. "Patient, always ready, know what they are looking for, and ready to pull the trigger."
The time is measured in months and years, not days or weeks.
The thing that people often forget is not the importance of finding (insert title game here), but the actual hunt.
Never be discouraged, that is the wrong mindset.
If a potential buyer knows someone is attempting to rape and extremely overcharge for a game, calmly ask a simple question to the owner, "Is there a small bar of gold bullion inside the cabinet, that I should know about?"
Don't expect to be invited back ever again.
Normally, you probably will not want too.
Know what you are buying with the title, the history, production run, and evaluation of game condition based on age and system generations. Do homework, if you are not an expert of a specific manufacturer. Alternatively, ask for help.
Best of fortune.