Are non-prescription contacts bad for your eyes??

like the ones you can buy at the drug store, beauty supply stores, etc.

Where are you from? I imagine they would be bad because they would not really be the right shape for your eye. But where I live (WA state) there is no such thing as non-prescription contacts. A prescription is required for ANY kind of contact lens, including novelty lenses like the cat's eye or vampire ones that don't otherwise alter your vision. You certainly cannot buy them at drug stores.

I dont think there bad for you they just arent needed cause they dont help so it would just not give your eyes air so I guess they are

if you need corrective lenses you would need a prescription and if it's just for colour lenses, I'd want to make sure that they don't damage your eyes. An eye doctor, or lens specialist would be better informed on quality of contacts. You don't want to damage your eyes.

They are not bad in them selves but if they don't fit properly they can mess up your your vision while you wear them and make your eyes hurt. It's okay to wear them for a special occasion if they feel comfortable but it they distort your vision or move around in your eye your should take them out. You also need to know how to clean them properly and how to put them in and especially take them out otherwise you can scratch your cornea.
It's really best to get your contacts from a doctor, if you are looking for some sort of special effect most doctors can order those contacts for you if they fit you. There is no universal contact so keep that in mind.

First of all, why are you wearing non prescription contacts? But if you have them, the only time that I can imagine them being bad for your eyes is if you don't take care of them and clean them, etc. So unless you change them out every day, you do need to clean and care for them as you would prescription contacts, because you are still putting things in your eyes.