You can choose from several suppliers, American or foreign (Commonly, China and / or Europe).

America / USA
A very new industry with the majority of USA eCig Suppliers, Distributors and Retailers providing electronic cigarettes that are made in China and then relabeled and sold under several brand names. In fact all current models are made in China. The difference is in the quality of the product a supplier / distributor purchases in bulk for resale. The general public is not usually aware that China based manufacturers will offer products at different quality control tiers resulting in different pricing and quality control.

USA Retail Store locations including Mall's
SmokingEverywhere Electronic Cigarettes, Blu Cigs and Njoy have been the leader in establishing retail locations which includes several big box retailers such as Walmart and H.E.B.. You will commonly find retail establishments such as smoke51 and smoking everywhere in major mall's offering a two piece electronic cigarette model.

These model are two piece units that usually requires you to purchase prefilled cartridges per use which can be very costly to the consumer. When buying from "brick and mortar" retail establishments you should expect to pay retail prices as overhead is higher. In recent months the GreenSmoke Cigarette has also appeared in many retail establishments.

Currently BluCigs, Smoke51 and Njoy electronic cigarette models are offered in a two piece system and only offers replacement cartridges. If you are looking for a Blu Cigs alternative or a Njoy alternative the 510 and eGO models are very durable and powerful. Purchasing models that allow for eLiquid / eJuice refilling by bottle can reduce expense and allow for a greater variety of nicotine level and flavor options.

Europe
Europeans have benefited from Electronic Cigarettes for nearly a decade. It appears the best selling British eCig sold by a British supplier is the EVO which seems to be a good unit as a good amount of positive feedback has been found. However this unit is made in China just like all of the production model electronic cigarettes. Currently the 510 models are at the forefront of the industry providing stong results.

China
Be very careful. The lack of regulation has resulted in sub-standard products being sold. There are a few honest suppliers but you will likely get a bad "copy-cat" unit (very likely). Even though many units are made in China and shown on the internet for half the price many units are poor in quality as the electronic cigarette manufacturers deal directly with distributors, suppliers and retailers and not to the general public.

Many recent forums have pointed out knock off models, especially regarding the Joyetech JOYE510 models. These China based companies have delivered products that have caused overheating (burning the lips) and several other issues (according to electronic cigarette forums subscribers). Currently for every Joyetech model there are over one hundred known knock off manufacturers with production mostly in Vietnam and Indonesia. Joyetech has attempted to curb this in may ways and more recently is taking steps to form "Authorized Dealers" to exclusively distribute Joyetech Product.

Considering you are inhaling vapors from these units into your lungs, you want a well made unit. You do not want battery leakage (common problem) or any sub-standard parts which could cause harm to your health.

E-Cig Scam Sites
Several ghost sites have been built that have very similar website domain names in comparison to the official website. In reality they are scam website's. When dealing with foreign suppliers double-check everything! CigsZee and Zeescigs (www.Zeescigs.com) Zees is a prime example.