What do you consider cheap?
Tractor Supply sells pretty inexpensive incubators though in my opinion they are a little harder to work with then a slightly better little more costly incubator. The Tractor Supply bators are a little more touchy with the heat and harder to keep accurate also they don't have fans to circulate the air. There are many many people here Im sure even in this hatch a long that do use the Tractor Supply incubators with good results after learning all the fine tuning they need to get good hatches. If you decide to go that route just ask many questions on here and people will surely answer you to help you get the best results possible.
I personally use the Hovabator 1588, its a good incubator and I have had much luck with it and great hatch rates, so much that I got two. To me its almost a set it and forget it type incubator with little fussing with it. I have been happy with them.
I hope others will chime in and give you more suggestions on some inexpensive incubators.
I personally love love the still air...just getting a Tractor Supply in our area..will be open this month! I'm pretty excited. Will have to go check out their bators....it really does take a few times to know that those still air bators are ...touchy...only need to tweek it a tiny bit, and you will more than likely get a real different temp..higher or lower, which ever way you were trying for..so, best to get that bator set up a few days ahead of time to get it where you want it, but like I said, I really like them, get great hatches from them..I hand turn.