about ov chipkaart
The OV-chipkaart is the payment method for public transport in the Netherlands. If you carry an OV-chipkaart with you, you no longer need to think about strip tickets or metro tickets.
It's possible to either get a personalised card, or a general one which you can deposit money on. There are plenty of machines around train stations where you can deposit money on your card. Its also possible to check your current OV balance using these machines.
You can also find machines ( which have a grey / red color ) where you can buy disposable tickets, which you can use throughout the entire day depending how much you plan to invest. Though keep in mind that you cannot pay using cash.