Hi Karen: The product looks remarkably like a cigarette. It consists of three parts: A battery, an atomizer, and a cartridge. The cartridge is pre-filled with a solution that consists of propylene glycol, water, nicotine (or not) and a flavor to replicate the taste of traditional smoking. Most suppliers offer cartridges containing levels of nicotine such as none, light, medium, and high.
How it works is that when you puff on the mouthpiece end (the cartridge), the battery kicks on and the atomizer creates a vapor from the heated liquid stored in the cartridge combined with the air you drew in. The vapor looks like smoke, but it doesn't last as long. It lasts about the amount of time as the breath you exhale when you are outside on a cold day.
NOTE: Propylene glycol functions to provide the vapor mist that looks like smoke and to suspend flavor. Propylene glycol is on the FDA's Generally Recognized as Safe [GRAS] list of substances for use as a direct food additive. Propylene glycol is also used to create artificial smoke or fog used in fire-fighting training and in theatrical productions. According to the World Health Organization, the acceptable dietary intake of propylene glycol is 25 mg of propylene glycol for every kilogram (kg) of body weight.
Most batteries have a light on the end that lights up when you puff on the cigarette. This lets you know that the battery is working. The one I have blinks 20 times when the battery is low so you can change over to your spare and recharge the one that is low.
The starter kits tend to include two batteries, a charger, atomizer, and a starter pack of 5 cartridges. Costs range from $80 to $150 for the starter kit. The cartridges cost about $2 each. Mine is supposed to be the equivalent of 1/2 a pack of cigarettes, but is lasting me twice as long as a half pack of tobacco cigarettes did.
There were some stores and shopping mall kiosks selling them, but curently your best bet would be the internet.
The FDA began seizing shipments of products coming in from China in late April. The FDA's position is that this is a "nicotine delivery device" that has not been approved by the FDA. [*ahem* So were the tobacco cigarettes that I used to smoke!] The company that I bought my product from (NJOY) is currently out of stock, due to the seizure. Another company has filed a lawsuit against the FDA and if it is successful, it should result in the release of all such products.
There quite a number of suppliers, and there is bound to be one that has product. Try a Google search for "electronic cigarette".