“If you have to ask how much it costs, you can’t afford it.”

That memorable putdown is widely, though some scholars say wrongly, attributed to J.P. Morgan, one of America’s top tycoons at the start of the 20th century.

But whoever created that monetary maxim, it came again to mind with the news that Boeing is slightly raising the prices of its — and our — Dreamliner 787s.

The “Grapevine” column in last week’s Post and Courier Business tab reported that the retail price tag of 787 models is climbing about 1 percent this year. That means the 787-8 will list for just under $212 million, the longer 787-9 for $249.5 million and the 787-10 for $288.7 million.

But hey, high-volume purchases generally lower the per-plane price. According to our Grapevine, “Aircraft list prices are somewhat symbolic because buyers typically negotiate big discounts on bulk jet orders.”

And products manufactured in these parts, and pretty much anywhere else, typically don’t cost roughly a quarter of a billion dollars each. So if for some misguided reason you wonder why Boeing’s 2009 decision to build Dreamliners in North Charleston was — and remains — such a big deal, ponder just how high that Dreamliner price soars and wonder no more.

And regardless of what J.P. Morgan did or didn’t say, don’t even dream that knowing how much a 787 costs means you can afford one.