With 3-5 chickens you will likely only get about a dozen eggs a week give or take, with them taking time off on really hot days and in the winter. You can grow some supplemental feed, but of course you will have to buy the seeds and the chickens will eat a lot. You can reduce feed bill by letting them range provided there are adequate greens and bugs. But it's really not fair to the birds to keep them without feeding layer feed - they need the calcium and nutrients. I'd do some more research before you get chickens - most small flock owners keep them as pets and you will spend a lot more on them than you think. I'm not trying to be rude, just making sure you have realistic expectations for the safety of the birds as well as your own welfare. It's much cheaper to buy a dozen eggs at the store than to raise your own. Good luck...
x2 - excellent advice!