Mobile phone
When I was in Junior highschool (high school) and it was the first time where (that) mobile phone becomes (became) popular here. I don't know exactly the year but I remember my older brother was the first person in my family who bought a mobile phone, It was a nokia 8210 serie(s).
In indonesia there are 2 bill (billing) systems, prepaid and postpaid. Most of us use pre-paid for mobile phone. And for pre-paid there are 2 ways to top up your account, buy a card that contains code to top up your account by yourself or the seller transfers some amounts of credits using his/her phone to our account ( we called it "Electric top up" ).
Time passed so quickly and technologi (technology) have (has) been growing so fast. We can do anything from phone nowadays.