craigslist is a good place to look. I have gotten many chicks from there, they're some really great people on craigslist, but obviously some not so great people. there is the rooster problem too though. Depending on how old you want them to be, you could try a place like mypetchicken. I highly recommend them. you could also look at your local feed store, some have chickens in the spring.
I say that, because last year I got into chickens and just wanted a few for a variety of different colored eggs. By a few - 4 at the most. I know have 30 chickens, from different sources - most from Craigslist.
My advice to you is to research chicken breeds first before acquiring chickens. And really put some thought into how NOT easy chickens CAN be. If you are an animal lover and cannot stand to see anything be sick or suffer - understand chickens can be quite challenging in that arena. My friends made it seem so "easy" - which this is how they accomplish that, one single purchase for their chickens and they DID NOT get attached to the birds. I complicated my situation with no research, I love all animals, and made multiple purchases within 8 months from different sellers. I have spent more money on vet bills and had my heart broken 4 times during my 11 months of owning chickens.
I commend people who can cull their birds, whether from sickness or for food - so wherever you fall in the spectrum is NOT a judgement from me - I'm just giving advice since you are asking for it.
On Craigslist, I have found that there are NPIP certified breeders - this means that they follow some guidelines that are regulated, so their birds should be pretty healthy when you buy them. I'm not implying that the non NPIP people will have sick birds - but I have several experiences with non NPIP purchases, and now I have a flock that have known exposure to Mycoplasma Gullium (my spelling may be off). Also, Somewhere along the way I purchased birds with roundworms and coccidiosis. My flock, now treated, appear ok, but ethically I can't sell my birds unless I disclose the above to buyers and let them decide if they want to manage birds with MG.
I suggest reading the emergencies and diseases forum, and see how common it is for chickens to become susceptible to falling ill. Also, again, research chicken breeds - and maybe find the best fit for you and your lifestyle. After by 11th chicken purchase, I fell in love with silkies and now desire to have flocks of only them, polish (with hopefully a frizzle), a few true americuanas, and a couple of Easter eggers. But the others I have purchased are mine until they die - and no I won't cull any of them, even the small flock of four roosters that have their own coop. And roosters can be really mean - and deadly to hens if the ratio is off in the coops they are contained in.
I LOVE having chickens - I just wish someone had given me this advice before I naively bought "a few." Good luck with your endeavor. Know that straight run chicks mean the gender hasn't been determined, a pullet is a female, a cockerel is just want it sounds like - a boy. Most roosters are free by the end of summer on Craigslist. If you think you may end up with more than one purchase, NPIP and vaccinated chicks (mereks disease at least) are something you should consider when you go to buy. And I apologize for the long post!