My most expensive firearm is probably my 4" SS Ruger GP100 on account of the amount of ammo I feed it. The revolver itself was rather inexpensive compared to other shooting irons I own but it makes every range trip and gobbles up lots and lots of .38 Special and .357 Magnum cartridges.
I have a Beretta 16 gauge SxS that would make many, many truck payments if I sold it. I'd never sell it it as my father-in-law entrusted it to me vs. his two sons.