Personally, I would never buy chicks from a feed store again.  I don't recommend it.
I have only purchased chicks from 2 feed stores, and this is my first backyard flock.  But here is my experience.
I knew what I wanted.  I wanted leghorns and RIRs.  My local feed store (good reputation) sold me 3 california whites (leghorn cross) and 3 brown leghorns, all pullets.  These chickens turned out to actually be 1 cal. white, 2 gold sex links, one of which is a rooster, and the other three were speckled sussex, not leghorns.  I am happy with my birds, but they didn't know what they were selling me!!!
The other feed store, which is recommended here in Phoenix by everybody, sold me several different breeds - they at least knew the breeds of their chicks, but they were all sick.  I ended up loosing 1 of those chicks, plus those sick birds made the first six sick, and I lost 2 of those.  
The chicks, while separated by breed, were in a closed in brooder with dead chicks and filth.  How can that NOT breed disease!?
Now, if I bought more chicks, i would go to another feed store in the next town north of here.  This one will take my small order and then take other orders.  Once she has orders for at least 25-50 chicks, she orders them.  You pick them up the day they come in and they are never hanging out with other chicks in a filthy environment.  They come straight from the hatchery and you can get the variety you want.  Very smart, I think.
There are hatcheries that would send a small batch, but you are limited to the breeds that they have.  
Just my 2 cents.  Hope that helps.
As far as cost goes, the difference between $1 and $2 for what you want is so minimal.  Who cares!!  
The real cost for chickens is in feeding them!!! and housing them!!  Expensive EGGs!!!!!