My Buff Sussex were from a breeder and cost $15 each and were well worth every penny. I am eagerly awaiting some Speckled Sussex and Light Sussex from the same breeder, same price per bird and then there is shipping as well.
I just purchased some White Rocks from Cackle Hatchery for an entirely different purpose, 25 cockerels @ 1.45 each, 5 pullets @ $3.00 and shipping 23.10.
Good birds bring higher prices. Rare birds bring higher prices. If it is a breeder, who diligently breeds and culls to bring the birds to their fullest potential, it is well worth the money, unless you aren't into that.
So the flip side is, if you simply want a bird that will lay an egg, go to your local farm store or such.Many of those birds aren't often truly purebred birds even though they carry a purebred name and are much cheaper. If they are like our farm store they are all mixed in together and nobody can tell you what they are anyway. They do usually have a bin of "pullets", ($2 - $3) so at least you have a better chance of getting hens. My pricier birds are straight run, no other option and that's okay with me.
(I cannot discuss Cornish Cross meat birds in an unbiased manor after having raised 10 of them. They grossed me out so badly, it will probably take me another year to even consider trying again with completely different management methods, but they are the most efficient growers.)