Amazon prime wardrobe
The Amazon Prime Wardrobe box ships free both ways, and customers can fill it with clothing they pick out themselves.

Buying clothing online is tricky.

Amazon, in adding to its ever-expanding benefits for Prime customers, will now let customers try on clothing before purchasing it. The program is part of the new Prime Wardrobe, which Amazon announced Tuesday.

The program is similar to many "box" services, like StitchFix and TrunkClub, where a few clothing items are sent to the customer, who then gets to try on the clothing before deciding what to keep and purchase and what to send back.

Amazon gives seven days to make a decision, and shipping is free both ways.

The difference with Amazon's service is that customers get to choose their own items to put in their box, instead of stylists or algorithms. A 10% discount will be applied if customers choose to keep two to three items, while those who pick four items or all of them will receive a 20% discount.

You can also order a box as often as you wish. There's no monthly subscription like other box services.

Not all clothing sold on Amazon will be eligible for the Prime Wardrobe, but items that can be put in a Wardrobe box will be marked with a logo for the service — over 1 million of them, according to the promo video.