There's not much question about whether gas prices are rising, as can be seen by the new and ever-taller signs posted outside gas stations featuring prices. But what about the price of the gas prices? Those varied collections of digits don't simply grow on trees, not anymore. The last grove of wild price-berry trees grew in Maine's upper peninsula until a bunch of spoilsport geographers pointed out Maine hasn't got any upper peninsula. An effort to relocate them to the New Hampshire panhandle met with a similar fate.
The history of gas prices can be traced back to the Babylonians: one fragmentary proto-parchment a scant three cubits by five reads ``DXXXIX OCTANE .XIXIX'', showing that thousands of years ago it was much cheaper to get 89-octane regular. Mind, this was so far back that not only had they not switched to unleaded but they hadn't even invented leaded. The meaning was apparently unclear to the Babylonians, because they hadn't even invented Roman Numerals in that time -- Roman Numerals were invented by Leonardo ``Fibonnaci'' Pisano in 1202 -- and were pretty hazy on the concept of Rome and whether it would go anywhere too. It's more sort of sprawled than gone anywhere.
Even once they found out what Roman Numerals were there was still confusion since everyone was pretty sure that ``D'' is how the Romans wrote ``500''. The solution ultimately proved to be time-travelling pranksters who thought they should take a break from leaving soda bottles on Mars and such foolishness, and will be revealed to the world in 2144. Don't mention this to anyone without a spoiler warning. Spoiler warnings can be obtained from the concession stand in the lobby.
Today, gas prices are generally obtained through mining: the always critical 9's come principally from just three former mountains in Pennsylvania and West Virginia, while the even digits are most often taken from Kentucky or the Ozark Mountains when the owners aren't looking. The odd numbers from 1 through 7, excluding 5, are dug from former silver veins in Nevada, and the 5 is produced by the one remaining open plant at Washington state's Hanford Nuclear Plant, by fissioning off either a 2 from existing 7's, or a 3 from an existing 8. A project in the Princeton Plasma Physics Laboratory in early 1994 triumphantly fused a 2 and a 3, but the operation could not be sustained enough to be commercially viable.
As long as gas prices have been for sale people have been trying to find ways around paying them, and one approach is to use prices that are not actually written down but are on electronic signs instead. While these are easily changeable and quick to respond to things like the ongoing vanadium crisis, they have disadvantages. A physically written price needs to be paid for once and then used however long the gas station owner wants. The electronic prices incur a continuous ongoing royalty for continued use of the typeface to either the Caslon family or the Mergenthaler heirs. Cross them at your peril.
And what of the quirk of ending gas prices with a 9/10? The United States has not minted a 9/10-cent coin except briefly in 1831 when the Second Bank of the United States was feeling all sarcastic towards President Andrew Johnson and looked foolish when they remembered Johnson wasn't in office and they meant to snipe at Andrew Jackson. This habit can be traced to the Second World War, when a War Production Board order of January 1943 restricted the use of the fractions between 91/100 and 99/100 for the war effort. For the duration prices went from ending in 99/100 down to 9/10, and people got so comfortable with that they didn't feel like changing back when fraction rationing ended in March 1945.
Many non-United States countries sell gas by the liter, rather than the gallon, and therefore they use the same prices but at different times. This inspires curious feelings of nostalgia or a sense of peeking into the future, depending on just when one happens to be overseas, and when one should be otherwise.
Trivia: The two rebel bands of Wat Tyler's Rebellion -- coming from Brentford in Essex and Gravesend in Kent -- entered the city of London on 13 June 1381. Source: The Later Middle Ages, 1272 - 1485, George Holmes.
Currently Reading: Challenge To Apollo: The Soviet Union and the Space Race, 1945 - 1974, Asif A Siddiqi.