Because Telstra has the largest mobile network in the country, it can afford to charge premium prices for its plans. Many customers are also loyal and value the Telstra name and network, and are willing to pay to get a plan directly from Telstra. Telstra, Optus and Vodafone also have to pay overhead costs to maintain their networks, which is one reason why MNVOs (who don’t have these overhead costs) can afford to charge less for their plans.