HI, my sister and friends are coming to visit jan 2017. she asked me about a TRANSIT VISA, they are in transit at MUSCAT for 2 hours, never heared of this myself as never landed there, QUESTION,, how does she obtain one, where from, and the cost if any, THANKS..

She wont need one, presumably flying in/out on Oman Air she will have boarding pass for the onward flight when she checks in at her point of origin.  They do have transit visas but that is for people who are leaving the airport.