Hello

and Welcome To BYC! A great place to start reading is the BYC Learning Center, lots of good articles on all aspects of chicken keeping
https://www.backyardchickens.com/atype/1/Learning_Center
Check out the BYC Coops section for coop ideas, you can usually build or have built for you a lot better coop than you can buy in those prefab kits.
https://www.backyardchickens.com/atype/2/Coops If you want to do a search, pallet coops are quite popular where people build coops out of recycled pallets, they can be as plain or fancy as you want.
Be sure to check out the BYC Breeds section for member reviews on a lot of breeds
https://www.backyardchickens.com/products/category/chicken-breeds and the Henderson chicken breed chart does basic comparisons of a lot of popular breeds.
http://www.sagehenfarmlodi.com/chooks/chooks.html
Going just by the numbers, the commercial White Leghorns for white eggs and Red Sex Links for brown are probably the two best layers around. If you want breeds that don't lay quite as well but will lay for a longer time, Orpingtons are one of the top picks, they tend to make really nice pets and be good with kids, Australorps, Sussex, Delaware and Wyandottes are some popular breeds that are usually pretty easy to get along with, they all lay different shades of brown eggs. The Easter Egger / often sold as Ameraucana by hatcheries, is the most popular green/blue egg layer, they tend to be nice friendly birds, and kids love the colored eggs.