I start up a new game: 1792, 23 years, advanced economy, highest glory and france as human.
These are the gold prices I see: militia 0, inf 63, gd 630, cav, hvy cav and lt cav 252, irr cav 63, art and horse art 252, how 189, army 63, corps 126, dip 378.
Naval units: fleet 63, 1st 157, 3rd, 4th, frig and priv are 63 and merchant is 94.
I save the game as test. Go back to the main menu and reload test and the prices for most units is higher, some are cheaper.
These are the gold prices I now see: militia 75, inf 100, gd 541, cav 403, hvy cav 516, lt cav 491,252, irr cav 214, art is still 252, horse art 289, how 289, army 75, corps 151, dip 604.
Naval units: fleet 151, 1st 252, 3rd 100, 4th is 63, frig and priv dropped to 50 and merchant is 100.
The way to get the gold prices into correct allignment even 20 years into the game is to start up a new game, same scenario, same parameters. Then go to game, open. Open your saved game and the gold prices will be in allignment with your current unit cost inflation.
In 1813, 1792 scenario I was able to get the gold price for a 1st rate to drop from 188 to it's correct price of 117.