When I first started out, I bought a prefab coop and built a small run. The run has grown in size over the last couple of years and I have still have the coop, but it is really flimsy and not secure. I lost some of my chickens earlier this year to a coyote, so I am in the process of building a new coop. I wish I had just built one to start with, but I learn as I go and was new to chickens about three years ago now. I have not added up the total cost of the new coop yet, but it will end up in the $600 range. I bought most of the materials new and have built most of it myself (hubby has helped when home). I have a cabinet shop next door to my work that has provided materials to me via the dumpster. I check it weekly to see what they have thrown away. A couple of weeks ago, I was able to get 3/4 melamine that I have now made into my nesting boxes. Anyway, I think I initially spent about $300 on the prefab coop so I will have over $1,000 into my chickens at this point, just in housing that is.
I have to say that I don't really pay attention to what it costs to get my eggs in terms of feed. I spoil my girls with meal worms all the time and have them trained to come when I shake them in the can. I let the big girls out of the run every afternoon when I can watch them. I am in an area with a lot of predators...coyotes, mountain lions, bobcats, hawks, owls, etc. so I have to be close by. My dogs also keep an eye on them, but I don't let them out of my sight. I also give them scrapes and buy them lots of veggies since we are cold in the winter and have no vegetation that they want to eat in the yard. Since we are kind of high desert, we don't have a lot of plants the chickens like to eat, but they do love to dig for worms and bugs in the leaves. I plan to plant a garden again this year, but can't do that until late May. The girls will get what we don't eat.
I have not sold eggs yet. I tend to give any extras away to people at work, friends or neighbors. We eat a lot of eggs, so I don't have that many left over. This year, I got six new chicks to replace the ones the coyote got (plus a couple of extra) so I should be getting more eggs this year. If I get a lot of extra eggs I may sell them and I think I can get about $5/dozen in my area. At that rate, it will take a long time to recoup on what I have spent, but I look at it as stress relief and a hobby I just love. That to me is worth every penny I spend on my girls.