People have been raving about oolong tea which is a traditional Chinese tea (Camellia sinensis) created through a distinctive process which consists of withering under the strong sun and oxidation before curling and twisting. Some even say that it has health benefits that include aiding in weight loss, reduction of risks of hypertension by lowering hypertension preventing cancer, possessing anti-ageing benefits and avoids cell degeneration, preventing diabetes and digestive disorders, promoting stronger bones and teeth, and sharpening mental skills, etc.
So to answer the titular question, here are some places where you can buy this little tea wonder:

• Go online

Here are a few sites where you can buy oolong tea online.

Teavana.com

• It is the official website of Teavana which is a specialty tea and tea accessory retailer based in Atlanta, Georgia. It currently operates 150 company-owned branches in the US and Mexico. From their website you can shop and choose from a wide variety of tea. Their oolong tea comes in many different variants and buying them is just one click away!

Artoftea.com

• They claim to be an award-winning boutique importer and wholesaler of organic tea and specialty tea. Their products include loose leaf teas, organic iced teas, organic chai tea, organic white tea, organic green tea, organic tisanes, organic oolong tea, pu-erh tea, yerba mate, pyramid teas and bulk teas. To see more of these choices and get an "art of oolong tea sampler", check out their website.

Adagio.com

• They also have a wide selection of teas at a good price and their oolong tea comes in a lot of variants. Each product has a costumer testimonial which makes it very appealing, enticing and tempting to just shop away and experience for yourself the aroma they are talking about.

Amazon.com

• Amazon provides a list of websites that sell oolong tea which makes it easy for product and price comparison.

• Stores

Whole Foods

• In the Whole Foods Store, there's a tea bar that shows you to a wide variety of tea including oolong tea.

Trader Joes

• At fair prices, you can choose from a great selection of Trader Joes organic green teas.

In addition to this, one should know that most supermarkets stock one or two brands of oolong tea, but they are usually generic oolongs and are not of the highest quality. Asian stores, specifically those catering to a Chinese customer base, typically carry oolong tea as oolong is popular in China and many other parts of Southeast Asia. Health food stores sometimes sell oolong tea. Tea shops that specialize in loose tea surely have oolong tea in their stock.

If you can afford it and want to get the best quality of oolong tea, you can go to Fujian province in China. Most of the Chinese oolong tea is grown in the South-China Fujian Province.