Really depends on the breeder. I don't like to pay more than 30-45 a pair for birds that aren't laying yet. 50-100 a pair is fairly normal for large fowl birds over 6 months I would say. But that can vary wildly. Shipping is expensive too, but it evens out in cost of feed to raise, already getting good quality etc.
Example (real numbers for me earlier this year):
Eggs - 2 dozen eggs @ $35 + $15 shipping means $100 total.
21 days later- Out of that I got a decent hatch for shipped eggs, 13 live chicks. Of which I'd say maybe 2 are going to be good quality, but won't know for sure until they're at least 6 months old or longer, it's about $1 per week per chick so $13 x 36 = $318 total is now at $418. Note that some breeds of large fowl still aren't breeding age at 6 months.
Scenario 2:
Shipped an 11 month old cockerel and a two year old hen, Langshans so BIG birds. But I see pictures, they're mature birds, its a reliable breeder, these birds are a great foundation.
One pair $75, shipping + box $175 roughly
Hen lays an average of 4 days a week right out of box, meaning while the shipped eggs were incubating I now have a dozen of my own eggs to hatch. Local eggs hatch much better (due to not going trough USPS trouble) 11 chicks.
$1 a week per bird is probably an exaggeration for adults but we'll stick with it.
Final result 13 birds. Cost = $256 (three weeks of feeding adults to get eggs or other chicks ) to have the same result. 2 quality birds, but since we have chicks there's potential for more quality there and we're already able to keep hatching.
Edit: and that's assuming a 50% hatch on shipped eggs, that is getting extremely lucky. I get 95% hatch rates on local eggs, I'm averaging right now around 25% for the year on shipped eggs (probably 15 dozen in all? thankfully haven't paid for a lot of them)
Edit 2: it gets even cheaper if you can buy shipped juveniles (or are into bantams) probably cuts that shipping cost in half, easily.