Anyway, I think from various cards only FLAZZ Card that can be used to buy ticket for both TransJakarta (known as Busway) and Commuter Line.
The things that you need to know about using Flazz Card is:
1. You can buy Flazz Card at certain bus stop for Trans Jakarta. The balance of this newly purchased card usually at IDR 20.000,- or IDR 50.000,- depends which one is available.
2. If you are using busway before 07.00 AM then the bus fare is only at IDR 2.000,- After 07.00 AM, the bus fare is IDR 3.500,-
Once you swipe the Flazz Card, the fare will be deducted from the balance.
3. If you are traveling around Jakarta with Commuter Line, the fare will be calculated from how far your route is.
4. You can use Flazz Card (and other cards from various Banks; you may refer from here) , to purchase ticket for more than 1 person. As long as you have enough balance to cover for them all.
5. You can only use Flazz Card (and e-ticket from Commuter Line) for yourself. Because the fare will be deducted after you arrived at the destination not before.
6. You can use Flazz Card until there is only zero balance if you travel by busway. Like for example, there is available balance about IDR 4.000,- Then you can use it to buy 2 tickets for morning fare. And only 1 ticket for one person after 07.00 AM
7. You can't use Flazz Card if there is only available balance : IDR 10.000,- to travel by Commuter Line. So you need to make sure you have sufficient balance.
8. If you have registered account with BCA, then you may have ATM that will enable you to top up the balance of your FLAZZ CARD. You may top the balance starting from IDR 20.000,-
If not..., then you probably just get a new one at the nearest bus stop for busway or at train station and tossed the old one. Or, keep it as a souvenir :)