LG is going to be your cheapest. I personally believe its also going to be the best for you to learn on.
Hovabators are preset to a certain temp I believe, so it takes a little of the "interactiveness" out, since you dont have to hone your skill of regulating temps. But Hovabators tend to be a lot more expensive.
LG's are good, but they can be tempermental at times. However the experience you gain from having to learn how to regulate temps and humidity with this incubator is priceless. Because you have to monitor and work to regulate temps and humidity, you learn how to troubleshoot incubation problems. I firmly believe that if you get an "automated" incubator that has presets on it, later on down the line when you end up with hatching problems, you wont have any knowledge to fall back on because everything has been automated up until that point. I really can't stress how much you learn with an LG.
I have an LG that I have used as a still air for 4 or 5 years now. I only recently upgraded it to a forced air by intalling a PC cooling fan. I love my LG and wouldn't trade the experiences I got with it for nothing. (Ok well mayyyyybe a redwood Humidaire)
If you dont want to invest a lot of money to get started, check out craigslist or other classifieds around your area. You may be able to find a used LG or Hovabator for aour $25.