So even if I had a really good car , you would not likely pay me more than that sort of car was being sold for elesewhere.
If I had an oil well , I might want to sell its oil for more than you were selling your oil for , but could I really keep my customer from knowing what you were selling at?
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The last car I bought was a 1985 Mercedes 300TD wagon with 168,000 miles.
I found a Taiwanese Coca-Cola exec that advertised it for $3K, and told me everything about it. He said he's sell it for $3K. Being as old as it was, it was hard to find a reliable price, but the wholesale was $2,800 and the retail was $3500. I told him I'd take the greyhound up to Atlanta and pay him the $3K if all was as he described. It was, so I did, in cash. Then I drove it home.
The car before that, a 1990 Benz 300D, was listed at $11,500. Retail was $12,500. I offered $10K cash, and it was accepted gladly and immediately.
I would not pay you retail. If I wanted to buy it elsewhere, I would have gone there. No car is a one of a kind deal, unless you are talking about a celebrity's car, and I don't need one of those.
If I had an oil well, why would I want your oil?
If you wanted to buy my oil, I am sure we could work something out.
If you are a buyer, assume it's a buyer's market.
If you are a seller, assume it's a seller's market.
Act accordingly.
If you are unrealistic, and, say, try to buy a round trip to Paris in August at December prices, you will either have to compromise the date or the price.