Because over one week I am going to Germany for worldcup, so I bought one GPS receiver Nav4all . The price is quiet nice , it only cost me 70 Euro and the mapping service is 1 euro per month. One thing amazing is untill 16 August I can use the service for free.

My colleague Sam , he is going to Germany ,too. But he has one GPS name TomTom. According to him, the price is 25O euro ! and the Service cost is also not cheap.

My question is why they are so different ? I do mean the market price here. after all, the functions are looks the same to me. I can't see the differences.