On Tuesday, the American mobile phone market took one step closer to looking a bit more like the European or Asian markets: free incoming calls, inexpensive outgoing calls, and a focus on data.

A Canadian startup, TextNow, just launched a new mobile service in the United States. For $18.99 per month, you get 500MB of data, 750 rollover minutes, and unlimited texting and incoming calls. In the US, it’s the norm for both the sending and receiving parties to be charged for a call. But nearly everywhere else in the world, only the person who originated the call actually pays.

“Incoming calls don’t really cost us that much,” Derek Ting, the company’s CEO, told Ars. “Carriers charge you anyway because they can get away with it.”

So what’s the catch? You have to buy one of their older-model Android phones: either a Samsung Nexus S for $89.99 or a Samsung Galaxy S II for $119.99. (Another catch: after the first day of business, the company says it’s sold out.)

TextNow states “everything goes over the Internet (for both texts and calls). It uses your Wi-Fi connection when it is available. When there is no Wi-Fi connection, it uses Sprint's nationwide 3G and 4G network.” (The company is a mobile virtual network operator [MVNO], which means it buys spectrum and tower access from larger mobile carriers.)

“We are moving to a model where in-network calling is completely free and unlimited,” Ting said. “Right now as it currently stands, Wi-Fi to data network handoff does not work, so the call will drop and also vice versa.”

Unfortunately, those of us (like yours truly) who have an unlocked GSM smartphone and would like to try out TextNow can’t do so.

“We do realize there is a huge demand for GSM [bring your own device], but there are no immediate plans [to expand beyond our current offerings],” Ting added. “Despite Sprint being CDMA, they have been the most cooperative for an MVNO in the States.”