If you start a thread by telling people NOT to answer you a certain way, that is a sure way to NOT get the answer you seek..

An incubator can be anything from an old sliding door pop cooler, a fridge, a freezer, an igloo cooler (plastic or styrofoam), a walk in closet, or even a glass aquarium. You can buy them premade or you can make it yourself.

The biggest things are that it is insulated well enough to hold heat fairly well. The heat source is placed correctly to allow for even distribution. A computer fan is used if there is too much up/down & side/side varient in temps. And like Deborah said, #1 most important thing is the thermostat controlling the heat source. Which can be mere flexwatt or even lightbulbs.