Leopard Geckos attain a maximum length of about 7-8inches so they dont require a big cage. For a single adult, I would recommend using at least a ten gallon aquarium. if you want to add more I would increase the cage size by ten gallons for each gecko you are going to add, (ie one gecko- ten gallon aquarium, two geckos-twenty gallon aquarium, three geckos-thirty gallon aquarium, and so on...). This rule of thumb can also go for babies and juvenilles. However, I would not recommend housing babies together because it is very stressful for them and it can lead to major problems. NEVER HOUSE TWO MALES TOGETHER BECAUSE THEY WILL FIGHT TO THE DEATH. You can also use rubbermaid containers or homemade wooden cages, but whatever you use make sure it has at least one square foot of floor space for each gecko you have and that it is tall enough that they cant escape.
The substrate can be anything you want it to be. Just make sure it is not toxic to the animal. I would recommend using either sand, newspaper, paper towels, alfafa pellets, or astro turf. I would also recommend using peat moss, I have used it for a few months now and have found that it is great. It can be purchased at any place that sells garden supplies. If you use sand make sure it is washed playsand that you can buy at toys R' us or home depot. Dont use sand for Leopard Geckos that are under six months of age. This is because at this age they are more likely to ingest the sand and block their intestines than older Leopard Geckos. If this happens then they most likely will die. If you use astroturf, make sure there are no frared edges just incase the Leopard Gecko might eat it and get impacted. Whatever you use make sure the substrate is kept clean and replaced periodically. NEVER USE PINE OR CEDAR AS THE SUBSTRATE BECAUSE THEY ARE TOXIC TO REPTILES AND WILL KILL THEM.
I would recommend using wood and rocks to decorate the cage. This way the cage will sort of resemble the Leopard Geckos natural habitat. The wood I recomend using is sandblasted grapevine or sterilized driftwood. Driftwood can be sterilized by putting it in the oven at 200degrees for about 30 minutes. Always keep an eye on the wood to make sure it doesn't start on fire. The rocks can be small 5 pound boulders that can be found everywhere, also make sure they are sterilized the same way as the wood. These are just recommendations on how to decorate a cage, do it anyway you want but DONT USE PINE OR CEDAR BECAUSE THEY ARE TOXIC TO REPTILES. Ans also make sure you have some sort of hiding spot for the leopard gecko. These can be a miracle whip container turned upside down with a 1 inchX 1inch hole cut in the side or one of those half log decorations that are sold at most petstores. Whatever you use make sure it wont collapse on the Leopard Gecko. Have at least one for each gecko. Another thing you need is a humidity box. For this, I recommend taking a miracle whip container or tupperware container that is big enough for the leopard gecko to go in. Once you have one, then cut a whole in the lid that is just big enough for the gecko to get into. Then fill the box with either moist paper towels or moist peat moss. Whatever you use make sure it is always moist. Without a humidity box a Leopard Gecko might have trouble shedding.
To heat the cage I would recommend using an incandescent light bulb in a reflector dome placed over one end of the cage. The reflector dome and light bulb can be purchased from home depot or walmart for about $8. The temperatures in the cage should be (all in degrees fahrenheit) 80 in the cool end and about 90 in the warm end. To heat the cage you can also use a heat pad that can be purchased from any petstore that deals with reptiles. I would only use this in conjuction with the reflector dome in cooler parts of the country. It should be wrapped in a towel and placed under one end of the cage. The wattage of light bulb depends on the cage size, try out different wattages untill you get the closest to the temperatures mentioned above. NEVER USE HOT ROCKS, BECUASE THEY DEVELOPE HOT SPOTS AND CAN SEVERELY BURN YOUR LIZARD.
Leopard Geckos are nocturnal so they don't require any sort of special lighting. The light from the heat lamp should be plenty. If you would like additional lighting then a normal tube ligth placed over the cage should be fine. Make sure you turn the lights off at night.
Baby Leopard Gecko should be fed a variety of live foods like crickets, mealworms, and very very occasionally waxworms. Always make sure that the babys prey is no more than 1/4 inch long and half that width. Anything bigger will cause irreversable damage to the Leopard Gecko. Juvenilles and adults can be fed appropiately sized insects like crickets, locusts, grasshoppers, mealworms, superworms, and an occasional waxworm or pinky mouse. Only feed pinkys and waxworms ever once in awhile because they are high in fat content. Make sure the prey is not longer than the distance between the eyes of the Leopard Gecko and half the width.
Every other meal should be supplemented with a calcium supplement and a multi vitamin. the calcium can be grinded up tums or a product called rep-cal/ the multi vitamin can be herptivite. All these can be purchased from a petstore that deals with reptiles.
Selecting a Leopard Gecko
The Leopard Gecko you are looking to buy should have bright alert eyes. It should appear active and healthy. It should not have a fecal matter by the vent or deformities (crooked jaw, bent arm, etc). It should not have any external parasites or wounds (ticks, mites, bleeding sores, etc). And if possible, have the person you are buying from feed the Leopard Gecko before you buy it, This way you will be able to see if the Leopard Gecko is eating before you buy it.