Placing a price on the captive husbandry of any species, is no simple or easy task.
Several factors regarding some of the issues you have mentioned can have a direct impact on cost and regardless of the amount of money spent, there is never any real guarantee that you will be successful.
With that said, plan of spending anywhere from 500.00 to 800.00 for your stock as babies, this will be the price for each specimen. Ocassionally, adult specimens are available, but for much more, plan on 700.00 - 1000.00 If you do acquire babies, plan of feeding them for at least 5 years 2 - 3 times per week, you shoudl get a quote somewhere on kingsnake, regarding th eprice of feeders. You may, or may not, encounter health issues, but I would plan on putting away at least 500.00 per year and per specimen to cover such costs, perhaps more, pending you have a qualified veterinarian in your area.
Enclosures can vary, as you can build your own for as little as you care to spend and depending upon your mechanical abilities, or you can purchase a manufactured enclosure, or have one custom built. Again, you should research the classifieds and get prices.
Incubators are much the same as enclosures. Again, you can build your own for very little, or you can purchase one for as little as 40.00 on up to 3000.00. Again, you should research the classifieds, or look on eBay, as there are a great number of incubators normally offered there.
Heat and lighting, well you can go with anything from heating pads to heating the room! Again, you should research the prices easily found on the web. You should look at heat panels, heat tape, timers and rheostats.
You again have a broad choice in lighting. Some people who have
bred couperi use specific lighting techniques and some don't. YO ucan use both UV and incandescent, or one without the other. The price of bulbs and fixtures vary, so again, you should look at classifieds and dealers offerings to get prices.
If you are conducting research, I suggecst you do just that "research" It's too easy to ask for all of the answers. Hopefully, this will give you a start. Now, just hit the classifieds and dealers lists and do some window shopping. You can also add some change to your electric bill and cleaning supplies.
Good luck,
Jeff