What's better than having Sir Richard Branson invest your startup? How about getting the Virgin Group founder and some of the most successful entrepreneurs in the world to give you their best business advice--for free?  

That's what e-commerce platform Shopify offered with its fifth annual "Build-A-Business" competition, the winners of which were announced Tuesday. Tens of thousands of startups entered the online sales competition last October and had Shopify track their sales during an eight-month period. The six companies with the most sales during a two-month period get to send their founders to Branson's Necker Island in September, where they will receive advice and mentorship from entrepreneurs including Shark Tank's Daymond John and The 4-Hour Workweek author Tim Ferriss.

Other mentors participating in the five-day workshop include Marie Forleo, founder of 2014 Inc. 500 company Marie Forleo International, and Squidoo.com founder and book author Seth Godin. The startups that competed in this year's competition generated more than 4 million orders worth more than $250 million in sales, up from $120 million last year. 

"None of these companies existed eight months ago," said Harley Finkelstein, chief platform officer of Shopify, adding that the point of the entire competition is to inspire people who might want to start their own online businesses but who lack e-commerce experience."

Here are this year's winners. 

  • Leesa. The bedding company founded by David Wolfe sells mattresses for less than $1,000 and ships them directly to consumers. The best part? The mattress can be compressed to fit in a tall box that makes shipping easy.
  • Trunkster. Co-founders Jesse Potash and Gaston Blanchet built a product for entrepreneurs and other frequent travelers who live out of their suitcases. Trunkster makes a $325 zipperless luggage product with a built-in GPS and mobile charger. The company launched after raising $1.4 million on Kickstarter.
  • Shore Projects. London-based watch company Shore Projects was started by Jono Holt, Ellie Price and James Street, three friends who had never designed, manufactured and sold a product before. The company makes watches with a timeless design that can be worn in any environment and sell for around $180.  
  • Pavlok. The wearables company started by Maneesh Sethi aims to go beyond tracking behavior by helping consumers to actually change their behavior. Pavlok's $149 wristband product uses classical conditioning to break bad habits by giving customers a very low intensity shock when they do things like smoke, overeat, or bite their nails. 
  • Little Letter Lights Co. The Australia-based company founded by Lucy Nourse and her husband Rob makes lamps shaped like letters and other objects that illuminate children's bedrooms. The marquee-style lights sell for $99.
  • Coco White. London-based Coco White was founded by Jonny Teeling and Will Peirce to meet the demand for an all-natural teeth whitening product. Coco White's coconut oil formulation gives customers a "dental detox" and sells for around $31.