UV light is emitted by regular lightbulbs, by the sun etc. Reptiles do not need UV lights, they need proper temperatures, proper nutrients, proper living space, a proper immune system, and the ability to secrete away from light, prying eys, and any percieved source of stress, in short proper husbandry. UV lighting is a money maker for the pet industry after all they tell you to buy $20-$60 plus lightbulbs to keep your reptile alive, healthy etc, and to replace them every 3-6 months, what they dont tell you is in reality they buy those bulbs for $2-$7 each and mark them up big time, they also as FR said dont use them on their own reptiles (sometimes on their store animals, but not on their personal animals).
In short they sell you a $5 lizard for $25, they dont make much on it, but they make alot on the aquarium they sell you, the UV bulb they sell you, and other supplies. The pets draw you into the store, then its their job to sell the bank to you while your there.
I use 45 watt outdoor halogen flood lamps, and 50watt indoor floodlamps only, no "magic UV bulbs". I used to help run a petstore and help a reptile related business now, neither of us use UV bulbs or sell them.