Walletsaver is a free mobile app for the comparison of mobile tariff plans. We analyze phone calls, sms and internet usage by extracting user data directly from the smartphone. In less than one minute we are able to suggest you the most suitable tariff plan in terms of cost and also signal coverage, combining the signal strength with the location of incoming and outgoing calls. Users can finally discover the right tariff plan for them, saving time and money on their phone bill.