Looking for lavalier microphones to use with iPhone 6

I need to capture video of interviews, and so need to purchase two external microphones for each of us to wear. Was hoping to use my iphone to capture the video since my regular video camera does have an external mic plug. Suggestions for inexpensive yet decnt lavalier mics that would reach at least 6 feet? Would also need a splitter, I suppose, since I need to plus 2 microphone in at once.