There's another factor that the chrome shops figure when giving you a price.
The guys above that said chroming is being regulated out of buisness is correct , and there are different levels of finish. But , the other cost they figure is the cost of "replacing" your part. Since sometimes a part is destroyed accidentally , they also figure the cost of buying you a new part and refinishing it , therefore the "rarity" of your part figures into the price. In other words , if you take them a hood ornament from a 1932 Duesenberg , and it's pitted , but they tell you they can fill the pits , polish , and double show chrome it , then when completed it's lost all of it's definition and sharp edges and just doesn't look quite right , it's considered "destroyed". Not that they actually broke it or anything , but when it's not perfect and you're not satisfied , and it's obviously unusable on the quality of vehicle it's meant for , the you AND the chromer have a problem. From your standpoint they destoyed your part and you want a new one , and from their standpoint they've got a job they done thats unsatisfactory and are not going to be paid for , in addition to the fact that you want them to buy you another core and start again. So now , they have to go find a decent original 1932 Duesenberg hood ornament , which may be impossible to find , and if they do it could be $1000.00 PLUS another chance at redoing it.
Different shops use different formula's for calculating this risk , but I found this out years ago when getting a lot of custom chrome done , all good/reputable shops operate this way.
So , if you're talking about common parts like non-rare pulleys for a Camaro where they can just throw it in a pile if it doesn't come out right , this factor won't be too large , but really rare and unreplacable parts get doubled and tripled in price because of this.
Also they want to see it because just the basic shape of things make them hard to prep and polish , not to mention some things can't be chromed at all for different reasons such as soldered joints , indifferent metals , irregular shapes , or even just the condition of the part.
These reasons and a few others are why you'll never get a chrome shop to quote you over the phone , usually not even a ballpark figure.