To narrow it down , what would you specifically like to know. There is soooooo much info. And what do you mean are they worth it? Are you looking to sell eggs or make a profit or maybe trying to find out if its cheaper to raise chickens than say buy eggs or meat ?
Well first of all if I get them I am debating wether to get black Orpingtons or blue marans or bantam silkies. They would mostly be for money, sell the chicks to make money. I can't really tell what the chicks sell for for any of the breeds they range so much I have checked kijiji,Craigslist,online auctions and online stores the prices range from like 5-30$. And to top it all of I don't even know if you can make money if them !!
As a begginer no you wont make money selling chicks. If you want to sell chicks and acutally make money, you will need good quality chicks (or adults) to raise. Then hope you don't loose any to predators. Your also going to want an excellent coop/run/pen set up. You will have future customers wanting to visit to view your set up to see how your birds are housed and treated. When you see chicks going for $30 these are the highest quality show birds. You will need to really learn alot about genetics and make sure you have excellent starter birds. Not all chicks will come out quality. Breeding for money is not something you can just jump into unless you plan to only sell your chicks for $3 each and not have champion bloodlines. But thats all my opininon. I Personally would never buy a high dollar chick from someone who is just out to make a buck. People who breed and sell those higher priced birds breed to meet the specifications listed on the book Standards of Perfection . This book is a mush have for any breeder.
On top of all that, you need to figure your yearly feed costs, electric ( heat lamps for brooders, incubators, ect), cost of material for everything, cost of good quality birds, testing and any permits needed to sell live chicks, and your time and energy put into it. Also chickens molt a couple times a year and during those times the egg laying slows. They only go broody when they feel like it so most likely you'll need an incubator too. Then you also need to learn to use it, its not as easy as it looks or sounds. Trust me.
Now I'm not trying to discourage you, I just want to be realistic so you dont jump in thinking your going to make a huge amount right away.
I have to ditto Apyl, I do it for the joy, fun and hobby. I do make some money off my eggs and chicks, but, we have put around 7,000 into our coops, runs, free range areas, feeder, waterers, brooder s, and so on, most of the labor and designs were from my own sweat as to save on cost. It will take me longer than I care to calculate to recoup my cost. We started 10 months ago planning to have 3-4 chickens. It grew fast beyond that.