Want to try before you buy? These online retailers let you

Amazon is set to launch a service that lets customers order clothes, try them on at home and pay only for what they keep. It sounds novel, but Amazon is actually late to the party. Several online startups have offered try-before-you-buy options for items including jewelry, clothing, glasses and more.

It makes shoppers less nervous about buying online, the companies say, and also gives people a chance to touch and try on a necklace or shirt before splurging. The retailers also know that getting you to try something at home means you're more likely to keep it.

Some offer home try-ons for free, others charge a fee or hold a small amount on a credit card until the items are returned. All offer free shipping both ways. But if you forget to send the items back on time, or damage them, you'll likely have to pay the full price.

Here's how some of the services work:

CLOTHING

Trunk Club, which is owned by department store operator Nordstrom, sends a box of stylist-approved clothing whenever you want for $25 a box. You have five days to try on the clothes and send back what you don't want. You'll be charged for any items you don't return, and the $25 fee will be deducted from the cost of what you buy. Stitch Fix offers a similar service for $20 a box.

The Black Tux, an online tuxedo and suit rental service, will send over an outfit to try on for free for 48 hours.

GLASSES

At Warby Parker, you can pick out five frames to try for five days for free. The company does ask for your credit card information during the test run and will charge for frames that are lost or damaged. If you decide to buy one, you send the test frames back and the company will send new ones.

ELECTRONICS

Lumoid lends used cameras, drones and other electronics for a fee to help customers decide which one to buy. The rental fees vary: A three-day test of a Canon camera with a lens costs $57. Lumoid also lets users rent three smartwatches for $53 or three high-end headphones for $30 and up. If you decide to buy something, a part of the rental fee is deducted from the purchase price. And customers can opt to buy a used item or new one from Lumoid.

Founder and CEO Aarthi Ramamurthy says people are overwhelmed with the number of gadgets available, and Lumoid offers a test run. "Why not bring the showroom to the consumer's home?" she says.

Lumoid recently signed a deal with Best Buy, and shoppers at BestBuy.com will soon be able to rent out some of Best Buy's cameras and fitness trackers.

JEWELRY

Rocksbox sends members who pay $21 a month three pieces of jewelry at a time, including earrings, necklaces and bracelets. You can wear them and keep them as long as you want. If you decide to buy anything, keep it at home and send the rest back. A $21 credit is taken off the price.

For those who plan to get hitched, Four Mine gives you three days to try on three engagement rings at home. The test rings are made with metal instead of gold or platinum, and use a fake diamond to help it look like the real deal. The company places a $1 credit card hold for each ring until they are returned, and charges $50 each for ones that aren't sent back.

ALMOST ANY SITE

Still in its testing mode, Try.com says it has developed technology that lets shoppers try before they buy at many online retailers. Users pay $2.99 a month to add a button to their Chrome internet browser and a Try.com option shows up on any site. Click the link, and Try.com pays for the items. Members have seven days to try clothing, shoes or accessories and send back any items they don't want. If you keep anything, Try.com will charge you for it.

The monthly fee will rise when it officially launches in November, but hasn't set a price yet, says co-founder and CEO Ankush Sehgal. That same month, it also plans to launch a mobile app. Sehgal says members try about $500 worth of items at a time, and about 70 percent of customers buy at least one item.