For optimal egg production you would feed mostly commercial layer feed (in the form of mash, which is cheaper but can lead to greater waste, or pellets or crumbles). You can supplement with veggies etc, in which case it is important to have oystershell and grit (they are 2 different things) available. Most people feed free-choice, i.e. food available 24/7 and the hens eat what they wanna eat.
Vaccines are not really necessary under most circumstances. They may provide some margin of protection against some diseases but the majority of things your chickens might get are things you can't vaccinate against anyhow, and the vaccines that *do* exist are typically far from 100% effective.
Breed wise I would strongly recommend red or black sex-links, for economical powerhouse laying. (Leghorns would lay as well, eat marginally less, but are not very user-friendly to work with, whereas sexlinks are mostly pretty friendly and easygoing. They do not breed true however).
Make sure you've looked into your state's laws re: selling eggs. Sometimes they are inconvenient, onerous or stupid, but you would want to know that BEFORE investing in chickens ;P
If you read around on this site you will get lots more info on what is entailed in keeping chickens
Have fun, welcome to byc,
Pat