Before you decide to keep chickens, be sure to check with the local zoning laws. Many towns are now allowing chickens to be raised, with some stipulations as to how many you can have, and whether a rooster is allowed (most probably wouldn't let you have roosters) But have no fear... you can have eggs without the rooster (he is only needed to fertilize the egg).
So where do you get chicks? To start off, check your local feed store (Southern States, Tractor Supply Company) they usually have a "Chick Days' where they will have live chicks in the store. This usually only happens in the Spring around Easter. The feed store may also know of some farmers that hatch out their own and are selling them. We sell our and advertise in a local paper. Many places are using Craigslist also.
If you are starting bigger, check out the poultry hatcheries such as Strombergs, Ideal, Cackle. You have to order 25 or more. There is a site called My Pet Chicken and they will sell just a few chicks (you need to buy a minimum of 3). Chicks are susceptible to cold, so the more chicks sent the easier to keep warm.
You will need to keep the chicks warm, so start them out in a small "brooder". A brooder is a box of some type that has pine shavings for bedding, and a heat lamp. We add screen on top to keep unwanted cats from having a "happy meal" when we aren't looking. We have had wooden boxes that hubby, Jim, has built, and plastic bins from Walmart. Something to keep them contained and without drafts, because they need heat. You can obtain a heat lamp from Lowes, Tractor Supply, etc. In a smaller bin, a 60 watt light may be warm enough if the bin is in the house and away from drafts.
When we were living without electricity, we heated a large pot with hot water, wrapped it in towels and put it in with the chicks. They huddled close for warmth. You will know if it is too hot for them as they will be spread out all over the bin trying to get away from the heat. If they are huddled close to the light, they are too chilly. If they pile on one another, the ones on the bottom could get smothered.
Chicks eat medicated chick starter. (Do not give this to any ducklings you may come home with, as it could kill them). Do not give them wild bird seed, or anything other than the medicated chick starter. As they get older you can give them table scraps, greens... just about anything. Chickens will eat everything with relish except citrus and onions.
Water is essential. Get a waterer specifically for chicks so they won't walk in it, or dirty it up.