Nina Lowe and Andrea Campbell, who met while training for a marathon, decided to take the personal styling service one step further when they started Front Door Fashion in 2013. “For them, the problem was that they had closets filled with clothes, but nothing to wear,” said Britt Ecker, the site’s director of marketing. Their solution: a personal stylist who can send complete looks — clothing, jewelry and accessories — for occasions like date night, events or work. “A stylist pulls up to 20 items from our warehouse,” Ms. Ecker said, “and meticulously styles them in four to six complete outfits, mixing and matching pieces to get the most out of each.” Detailed notes explain how to wear each look. The average amount is $500 a box, she said. The trial period is five days; a $100 deposit is applied to orders or refunded in full if everything is returned.

The idea for the year-old Rockets of Awesome was born when Rachel Blumenthal became a mother. “I was excited to shop for my son but quickly found it a chore to find stylish clothes that didn’t cost a fortune,” said Ms. Blumenthal, whose husband, Neil Blumenthal, is a founder of Warby Parker, a pioneer of “trying before buying.” Her goal was to simplify the lives of parents by delivering a box of stylish, high-quality, moderately priced children’s clothes produced by an in-house design team each season. The company analyzes both behavioral patterns (what shoppers are buying) and children’s preferences (based on the profile parents create) to create a personalized box of 8 to 12 items, each ranging from $10 to $36; customers have 5 days to decide; and for those who care about such things, Gwyneth Paltrow is an investor.

Vanessa Stofenmacher, a founder of Vrai & Oro, a direct-to-consumer jewelry start-up, is counting on the try-on business model to revolutionize engagement-ring shopping. “If an engagement ring is a symbol of two lives joining together, we think the ring should be a joint decision,” Ms. Stofenmacher said. “The try-on feature allows her — or him — to select three designs and see the rings in person before committing, while still giving her partner the opportunity to choose the perfect diamond on his or her own.” Clients can test three sample rings for seven days in exchange for a fully refundable deposit of $50.

What if you want to shop across websites? Ankush Sehgal is a founder and the chief executive of Try, which for $2.99 a month enables customers to try on items for seven days from any online retailers. “In 10 years, we’ll look back and laugh about how in the old days you had to pay upfront for online purchases,” Mr. Sehgal said. “The real reason why you have to pay upfront is because merchants can’t trust consumers not to run away with the product. In today’s world, we can solve this problem with technology.”