Hello

and Welcome To BYC! Your state thread is a good place to post for local birds or to ask where people in your area are finding theirs
https://www.backyardchickens.com/t/248345/pennsylvania-unite
For breeds, check out the BYC Breeds section, there are member reviews of a lot of breeds,
https://www.backyardchickens.com/products/category/chicken-breeds and the Henderson chicken breed chart compares a lot of popular breeds
http://www.sagehenfarmlodi.com/chooks/chooks.html In general, if you want to replace your flock every couple of years when they slow down laying and you are looking just at the number of eggs, the various commercial Red Sex Links (they go by different names depending on the hatchery, Red Stars, Golden Comets, ISA Browns etc) for brown eggs, and the White Leghorns for white eggs are probably number one. Some other popular brown egg laying breeds that don't lay quite as well but usually will lay over a longer period of time are Sussex, Wyandottes, Orpintons, Delawares, Australorps and Plymouth Rocks, and of course Easter Eggers / Ameraucana for blue/green eggs and Welsummers or Marans for those dark brown eggs.
You don't need a rooster unless you plan on hatching your eggs. If you are going to have a small flock, you may want the extra hen for more eggs, instead of a rooster. Some roosters are friendly, no real way to know how any specific rooster will turn out though... they do add an extra dimension to the flock dynamics taking care of and protecting the girls as they can, and they are usually very pretty to look at.