According to the latest from Apple's testimony in the ongoing legal battle between Apple and Samsung, Microsoft struck a deal with Apple permitting the software-maker to utilize Cupertino's tablet design patents.
Apple claims it offered to license the same patents to Samsung for about $40 per unit (roughly $30 after discounts). However, the Korean manufacturer declined. Apple claims Samsung then continued to make their own mobile products which attempted to emulate the iPad's look and feel.
Presumably, this information indicates that Microsoft may pay royalties to Apple for every Surface tablet it stamps out. If the prices offered to Samsung are any indication, Microsoft may pay Apple between $25-$40 per tablet. Of course, this is a largely presumptive step in crude logic. This depends on whether or not those very same patents are applicable to Surface and what the Microsoft-Apple deal's fine print dictates. Those details may never be known.
Apple's patent case against Samsung has managed to elucidate a number of interesting but otherwise secretive bits of information. Thanks to legal documents made available through the trial, we've discovered old prototypes of the iPad and iPhone, showing that these concepts hail from ancient times -- well, 2002 anyway. Additionally, the case has revealed some solid sales figures for both companies while also shedding light upon a cooperative Apple who worked with Sony in order to flesh out their phone and tablet designs.
Apple claims that over $30.4 billion worth of Samsung's handset and tablet sales infringe on one or more of its iPhone or iPad patents.