The day to day care is generaly not difficult at all, but getting the set up right in the first place can be complicated, made worse by outdated opinions and conflicting infomation given by various sources. Pick a species you are interested in, work out what you want in an animal, i.e do you want something that is active and interesting to observe, something that will live in an attractive set up, something that can be handled? The three species you list are all nice animals with relativly simple requirements but they are not the only ones. They are also all very different, which seems to sugest you have picked them as they are recomended as easy to care for rather than because they are the species you are interested in. Try not to fall into the trap of getting a "starter" species just because you think you should if it is not something you are going to still be interested in later on, as far too many animals are passed around when their owners get bored. Not that there is anything wrong with the ones you have listed. I started with Leopard Geckos over 20 years ago and still have them today, and still think they are great lizards to keep, but make sure you get something you like as an animal, not just because they are easy to start with. Do some research on your chosen species, look online, speak to other keepers etc. You will find different infomation from different places, sometimes completly conflicting, but use common sence and logic, work out why certain things are meant to be done a certain way rather than just taking for granted that it has to be that way because somebody says so, and how it relates to how the animals live in the wild, and it will start to make more sense. Don't assume what the pet shop tells you to do is right, more often than not it won't be, in fact, if you can avoid pet shops all together so much the better. Once you are decided and know what you are doing, get your enclosure set up and functional first, make sure everything is working as it should, temps and humidity are staying at the correct levels etc, make sure you have a reliable source of food, know of a good exotics vet just in case, then get your animal from a reputable breeder/dealer. Make sure it is healthy, and preferably captive bred (with most commonly kept species this is not normaly an issue). If everything is right to start with then with any luck you should not run into any problems. Never forget that this is an ever changing hobby. New research, new products and new ways of thinking are constantly cropping up, so be willing to accept this and take advice, tweak and change details and opinions if necicary to keep providing the best possible care for your animals.