Digi-HUD Speedometer is 100% free it does not need a data / cellular connection to work.

DigiHUD Speedometer is a free digital GPS heads up display (HUD) that shows speed and distance information for your trip. Ideal if your vehicle speedometer is dead you want to check the speed or just want to know how fast you are driving.
Speedometer screen can be switched between the normal display and the heads-up display (HUD) mode which reflects the screen to see it as a reflection on the windshield of a vehicle which is more useful at night depending on the brightness of the device.

DigiHUD Speedometer Display following information:

• Simple interface and smooth functionalities odometer.
• Speed is displayed on a digital value.
• Precise speed and attractive display.
• The speed can be displayed in one of three different units: kilometers per hour (km/h) miles per hour (mph) or knot (nautical miles per hour)
• Car Speed Meter

The salient features of this GPS Speedometer App are:

• DigiHUD Speedometer for Car Bike Bicycle Trucks
• Accurate Odometer and trip meter for Cars Bikes Bicycle Trucks
• Accurate Speed in Digital and Analog Speed Meter
• Vehicle Tracking on Maps
• Maximum Speed Average Speed and Total Distance Covered for each trip