Do all satellite navigation systems (sat-nav) require subscription?

Typically, how much are the subscription costs? Thanks!|||Global Positioning System (GPS) does not cost anything. It is just a constellation of satellites that anyone can use as long as they have a GPS receiver (ie a Tom Tom or Garmin). You can get a GPS unit for less than $150, but you can also opt for a more expensive one. Some of the higher end models do offer real time traffic, sometimes there can be a monthly fee for that, but you can also just pay a little higher upfront cost and get real time traffic for a one time price.