Many people do not recommend hatching duck and chicken eggs together simply because they have different incubation requirements. Duck eggs take 28 days to hatch; chicken eggs 21 days, and humidity requirements can also be different. Also, since the chicken eggs will hatch a week earlier, the hatchlings and eggshell remains will dirty the incubator and possibly contaminate your duck eggs. Of course you can hatch duck and chickens eggs in the same incubator, but not at the same time.
As far as incubators go, lots of people use
Brinsea incubators--they are reliable, but also rather expensive (the smallest one, the 10 egg eco model is around a hundred dollars). It's better not to buy the cheap foam incubators at farm stores--like the Farm Innovators or Little Giant brands--they are difficult to work with, and have notoriously inaccurate temp and humidity gauges. I have a older model Little Giant(the older ones are generally considered to be a little better than the current model), and have invested a lot of money in it in accessories like a fan, egg turner, and multiple thermometers, so in the end they are not a very good deal at all. It is better to start off with something a little more reliable.
HovaBator incubators are an old favorite; they are foam also, but better quality. You have to understand that you get what you pay for in incubators. The cheaper they are, the more difficult they will be to operate. Do you want to have to deal with a cheap incubator that requires constant monitoring? Or one that is a little more expensive, and is easier for you to operate. I want you to have a good first hatch!
I understand the problem about money, I'm a teenager also
. Maybe you could ask for an incubator for Xmas.
