in my opinion there is no point of buying an incubator just use the method of the 4,6 qrts tub with 0.8 grams of water to 1 gram of vermiculite and leave it
i think if you dont have an U.T.H u can use a heatlamp or a normal clip lamp with a red bulb (low wattage) because i read that leopard geckos cant see red and use a florescent bulbs to provide them with d3 and if you dont want to use it its fine thanks
you can use an ordinary light and see if the egg had a pink or a rose colour and veins are visible then it is fertile if it was dull orange and no veins are in there then it is infertile ( candiling method is used for knowing if the eggs are fertile or not but i dont recommend candling)