looking for a cheap and effective diy incubator

[The_Dreaded_Pets]

so looks like i have a male and female pygmy bearded dragons.
now i have a friend that can lend me an incubator if im lucky enough to get some eggs this season as i wasnt planing on breeding until next season but i was wondering what the best diy setup would be as i figured since i start a new hob next week i shouldnt have much trouble comeing up with the funds to make something so i have my own for future use.

i have read somewhere about useing a styrofoam esky with a window in the roof bricks on the sides and water in the bottom useing a fishtank heater is this kind of setup good and if so can somebody please explain it in detail for me

thanks in advance for any and all help
cheers mick

edit - also any tips on incubation temps and humidity would be great