Before they had kids, friends Dori Graff and Mary Fallon considered themselves minimalists. Both women liked beautiful things, chosen carefully and arranged meticulously.

But once their kids came along, the two realized that parenthood brings with it a constant cycle of stuff: Toys, furniture, shoes, and especially clothing flow into and out of the household at an alarming rate. It's a cycle that feels wasteful, expensive and draining. They thought other parents might be feeling the same way. So they decided to tackle the problem head-on.

The duo created Kidizen, a free iPhone app that allows users to buy and sell used kids' clothing (or "pre-loved," as they say) through a virtual community of parents. Launched in December 2013, it already has more than 10,000 users across the country.

The idea might sound like an app version of Craigslist or eBay, but its founders say there's a key difference.

"People really enjoy connecting with another parent who's going to get their kid's stuff," Fallon says. "There's a memory attached to the thing itself. Creating that community is core to our essence."

How it works

Kidizen grew out of a previous digital venture, Itizen, which had a similar interest in thrifted items and the stories behind them. But when Graff and Fallon started focusing their attention on kids' clothes, Kidizen took off.

"Kids go through about 20 sizes in the first 12 years of their lives, seven sizes in the first two years," Graff said. "It's not uncommon for kids to grow out of things that they've never even worn."

With Kidizen, users can recoup some of their losses with a few clicks. Everything is done right from the app, from taking photos of salable objects to choosing categories, writing descriptions and setting prices. When you list an item, the app shows you how much you will make based on your listed price, automatically subtracting the PayPal fee as well as the 7 percent Kidizen fee. (Buyers can use any major credit card to pay, but selling is all through PayPal.) The seller pays for shipping.

Simple filters allow you to search the entire network for items based on your kids' sizes and genders, and you can create separate, customized feeds for each of your children. Like a social network, you can also "follow" particular sellers who have kids in similar age ranges and with similar tastes in clothing, plus create a feed that shows you any new listings from these preferred sellers. Although there is a smattering of toys and books, around 90 percent of Kidizen listings are clothing.

Randi Pivec of Golden Valley is an avid Kidizen user, turning castoffs from 2½-year-old Violet and 10-month-old Greyson into cash that she uses to buy more clothes through the app.

"Kidizen is similar to a small family-owned business — it has that feel to it," says Pivec. "It has a sense of community that I feel the other options lack. It's like we're this group of people that are united toward this one goal of selling our 'pre-loved' children's clothes and buying more awesome pre-loved clothes."

Plenty of options

Kidizen has plenty of competition. On the brick-and-mortar side are stores like Once Upon a Child and Nu Look. Online, there are stalwarts like eBay and Craigslist, and consignment platforms such as thredUP. For thredUP, customers mail in high-quality used goods and thredUP's staff sorts through and prices the merchandise. Then goods are listed on the thredUP site and profits are shared. Like traditional consignment storefronts, thredUP takes between 20 to 50 percent of profits.

Kidizen, which is run out of a quirky, colorful duplex in Uptown, is growing thanks to community support and eager investors. Apple has featured Kidizen in the iPhone App Store as a Best New App and Best App for Parents.

Earlier this year, Kidizen was asked to present at Google's Demo Day, after which AOL founder Steve Case presented them with $100,000 to grow their business. Graff and Fallon hope to expand Kidizen onto the Web or the Android platform by the end of 2014.

And they are constantly thinking of ways to change and improve their social network-focused business model. "We'd love to have a feature where people can swap appreciation pics, like 'Here's my daughter in the dress I just bought from you,' " Fallon said. In some cases, that goal is already being met outside of the app.

"I actually had one of my buyers send me a picture of her baby girl in one of Violet's outfits, and it totally made my day," Pivec says.

Sally McGraw is a Minneapolis-based style blogger and author of Already Pretty (www.alreadypretty.com).