If you are enterprising, you might get a better incubator for your needs by building one yourself. Of course, you might not have the tools or space, etc.
The $100 or less limits you a bit. There are some good incubators, but many are around $130/$140 or higher. Incuview 360 is a popular choice around $140. Many incubators are sold out right now, as well.
I bought the cheapest one I could find - a Little Giant Still-Air incubator for $49, and it holds 42 chicken eggs, but manual turn and no fan. But got some good hatches. I did just purchase the circulator fan for an additional $21. You can buy the egg turner for additional cost. Most farm stores have a cheap choice, up to pretty expensive, so start by looking at Rural King or Tractor Supply websites to begin a search. Incubator warehouse has some good information too, and sells supplies for make your own incubators.
Ive made my own small incubator as well. But it is pretty small, so went with the Little Giant.