So you’d like to wear colored contacts, but you don’t have or maybe you don’t even need a prescription for it. Then it’s good for you that they have made it possible to get color contacts just for cosmetic reasons. If you need to have contact lenses that correct your vision (if you have a near-sighted or a far-sighted vision), then you need a prescription for the color contacts to correct your vision correctly. If you have no problems with your vision, then you don’t need one. If you do need a prescription, visit an eye doctor to get one. If you aren’t sure if you do need, then also visit an eye doctor to make sure.
There are lots of people who wear color contacts just for cosmetic reasons and that is why there is also a non-prescription choice for them. But even if you don’t have problems with your sight, I strongly recommend you to visit an eye doctor. There you will check what kind of contact lenses are good for your eye since there are many different types of contact lenses made of different materials. I don’t think you want to take a risk to hurt your precious eyes .
There is no difference between colored contacts that you get non-prescription and those that you get with prescription except the fact that the one with prescription corrects your eye vision. You want to be sure which one you buy because if you don’t need correcting contact lenses and you got those, it will make your sight blurry and give you an head ache and maybe even make your current vision worse. On the other hand if you buy color contacts without the correct settings, well you can see how it’d be like by just not using any contact lenses or eye glasses (notice that putting on and taking off contacts is much more difficult than eye glasses).
Where can you then get color contacts without prescription? I’d say that in most online stores, you can choose which type to get and in many normal stores they also have the option to choose. Just make sure that they have the type you need. If you aren’t sure, at online stores you can contact them and at normal stores it’s easy to just ask the staff to make sure. Also you can of course just find an another shop where they clearly tell if you can get the type you need.