I am also new to chickens...I got day-old chicks two springs ago...mine came from my local Agway.
I am glad I started off with day-olds, as there is much to learn and there are so many potential trouble spots involved in hatching...have you read the incubating and hatching thread for long?!! YOur kids will learn a ton by raising day-olds, too, and you can hatch the next batch in a couple of years if you decide you want to try it.
In NY, the minimum purchase (according to
Tractor Supply) is 6 chicks. Agway insisted on a minimum of 15. You may need to order ahead if you want all pullets or a particular breed.
In regard to getting a roo, in my opinion, unless you need a roo for free range protection or for fertile eggs, they're a pain. They break the feathers off the hens' backs from breeding, cut the girls' sides with their spurs, and mine get snotty during breeding season, occasionally going after my legs when I go in the coop. Some roos are lots worse, some are friendly, but you never know till they grow up what you'll get. And you have kids...roos can really hurt a child.
I ordered all pullets, and still got two roos. Hopefully,
Tractor Supply uses a more reliable hatchery than Agway!
On the other side, roos are beautiful to look at, and I do like to hear them crow. Still, I'd have been much happier if those two birds had been hens...it's two more mouths to feed that aren't giving me eggs, and ARE causing problems, though as I said, I'm so lucky that they're minor problems... could be a lot worse!
As a side note...someone quoted $8 each as a price for chicks...maybe that's from a private person...hatchery chicks are not that much. Two years ago, the ones from Agway were $2.50 each, inclucing shipping. Good luck whichever way you decide to go!