I got to thinking about this question. The answer varies greatly. You can get hatchery birds...that may or may not turn out to be quality show birds. Showing Rod (Sultan) was proof that you CAN get a good bird out of a hatchery...but with that said, you arent going to get it consistantly.
Last year I ordered from McMurrayHatchery
You can click on this link and see the prices of chicks of many breeds there.
Now when it comes to rare birds, it is really the same way. Some will be quality, some will not be. All breeders want to think their birds are superior...who wouldnt.
For instance, the lady selling her Serama at the show. She wanted 55 dollars a pair. I wouldnt have paid her 25 dollars a pair, because what I saw was possible mixed blood of Old English in some. They may have been Class A's, but that doesnt mean a thing if they arent pure.
People that deal in Games are very intense with their stock. I have seen some want hundreds of dollars on up to a thousand for a good Game breed of chicken.
I dont keep games. The roosters must be tied out individually or they will fight to the death.
The females can be pretty intense too, especially if they have chicks.
Last year I paid 25 dollars for my pair of Silver Laced Polish I showed this year. That is a reasonable price for a good pair.
I paid 40 dollars for my pair of Giant Cochins this year. There was a pair for 80 dollars...but I just couldnt see the difference. I am sure there was a difference to the trained eye for cochins...but seeing as I dont have a trained eye for giant cochins...I was happy getting the 40 dollar pair.
So basicly it depends on the breed, the quality, the rarity.
If you look in the Market Bulletin right now you will see people selling one year old grown layer hens anywhere from 7 to 10 dollars each. MarketBulletin I prefer to raise them from chicks so they are tamer and will come to me. That is just a personal preference. Even though chicks are cheaper..you will end up spending money on feed, antibiotic, waterers, shavings, feeders...building them an outdoor pen or house...it never ends really...so it is just up to you what you where you want to start.
If you want to know what a quality bird looks like...find the standard for the breed you are interested in. It will tell in detail what that breed is supposed to look like to be the best looking bird.
If you are not worried about showing and just want a nice looking yard ornament..then you won't pay as much as if you bought a show quality bird.
Check around at flea markets, Farm news bulletins if your state has one, find a show, go to it and you will find plenty of birds to be sold. March 9th I believe there is a swap meet for a lot of us chicken folks. You find out a lot when you go to a show...dealers, breeders, that kind of thing.
Be warned...when bringing new chickens into an existing flock it is a wise decision to quarantine the new birds away from the established ones until you are sure the new ones don't have any diseases or mites to transfer to your existing flock. I usually quarantine for at least two weeks.
So, basically, chickens can cost a couple of dollars up to hundreds, even thousands of dollars...just depends on what you want, and what you want to spend.
I prefer to keep my spending reasonable. :)
Specifically for MYRDOG...the Silver Spangled Hamburgs are in fact a breed for sale on McMurray. Go have a look see. :)