rittert, you can always go to the library to use the internet for free.
Tarja, I don't remember where you said you live. I do sell mixed hatching eggs for $3 a dozen. There are almost always a good percentage of purebred chicks in there. And it would be all the kinds you are interested in except the orpingtons. Could also have a polish or a wyandotte mixed in as well though. Or you could put an add on Craigslist under farm and garden and say you want to get a dozen fertile eggs for the kids to hatch. (People will often give you better eggs if they think a kid is involved.)
Shipped eggs are awful. Unless you know the person you are buying from, I've found that people that sell them often send you mixed eggs or old eggs. I started trying to increase breeds by buying shipped eggs and it was a total mess. Also the hatchability is usually down. I honestly think a lot of it has to do with the eggs you start out with as well as how they are packed. I have shipped eggs to my daughter in Texas and packed them carefully and she has had a 90% hatch rate. But I have never gotten that kind of hatch from ones I bought on line. I also have at least that good hatching percentage and often 100% rate here.
Tell your husband if he makes a homemade incubator to be sure to spend the money to buy a computer type fan that runs on 110v or a small AC operated personal fan if he is building a larger box. With the design that most people use the temperature fluctuates too much before the thermostat kicks on or off. If you have a fan, it keeps the heat more even. This is extremely important. Spend $7 at
Walmart and buy a little digital thermometer that also shows humidity. Also be sure to have a place for a humidity pan.
These things may seem unimportant but if you want a good hatch they are vital when you build your incubator. Then don't rush it. Monitor the incubator for several days and make sure it stays on a fairly consistent 99.5 degrees. You never want anything over 102 or under 98 for a successful hatch. It takes time for the cabinet and everything to stabilize in temperature.
Hatching is miraculous. After several thousand chicks I am still thrilled with each and every new baby. I have a see through door on my hatcher just so I can watch them hatch.