large_4418792000The promise is simple: Sell anything, anywhere, from your phone. No matter where you want to sell it: eBay, Etsy, Craigslist, Twitter, or Facebook.

SellSimple is launching its iPhone app today that people with too much stuff can use to sell it to people with not enough, simply by snapping a picture, adding a price, and selecting any number of marketplaces to post it.

“Using eBay is way too complicated, and Craigslist is a little bit sketchy,” SellSimple chief executive Julian Sarokin said yesterday from West Hollywood, where the company is based. “This is a way to sell from your phone … an easy way to just get it done.”

Letting buyers easily get it done, however, has taken a significant amount of hard developer work getting it done. Initially, SellSimple was just a way to post and sell via your phone on the company’s own marketplace. After initial demos, however, advice from mentors and investors convinced the 21-year-old CEO and his 20-year-old cofounder that posting to multiple existing marketplaces with significant buyer scale was a better idea than starting with an empty storefront.

In other words: chicken, meet egg.

mzl.skvrvteb.320x480-75Those mentors and investors include rapper/actor Nas and musician/producer Dr. Luke — who has worked on albums for Katy Perry and K$sha — among others. Together with a few additional angels, they’ve injected $250,000 in SellSimple, making it more than just another app. Which Sarokin is well aware of.

“There’s a really big distinction between an app and a company,” he told me. “Our goal … is that we would become the new eBay or Craigslist.”

That’s of course no small goal. SellSimple wants to achieve it through user experience, a built-for-mobile buying and selling experience that is better than existing sites. And by providing an initial benefit of listing everywhere with one simple tool, easily. In addition, it has built the capability to buy items from eBay, Craigslist, and other sites right into the tool.

One question I had: Will eBay, Etsy, and Craigslist be OK with SellSimple posting listings to their sites and selling items from their services? Craigslist, for one, has had numerous disputes with companies like PadMapper that tapped into its listings.

“We haven’t actually talked to anyone at Craigslist yet,” Sarokin said. “But there are some other apps that do this, and I don’t think it’s gonna be a problem. PadMapper was pulling data, while we’re adding data.”

The app went live yesterday in anticipation of the the launch today, and Sarokin said that the reception has been unexpectedly good: #18 in the list of top free iPhone apps for lifestyle, without any promotion.

He expects to monetize the app with shipping integrations, a 5 percent fee if items are sold via SellSimple’s own marketplace, and commissions on sales of products on eBay or other listing sites. Items sold via other marketplaces, however, are free (minus any fees those sites might charge). And if you list your items for sale via SellSimple, the service will delete your postings on all site as soon as your items are sold.

Here’s a look at the app via video: