how to say this in english
if your cellphone runs out of money(is this right?). what should you say if you want to put money into it? charge calls in?

Question

Answer

Your cellphone runs out of 'credit'. 'My phone is out of credit' or 'I'm out of credit'

To recharge a pre-paid account, you 'top up'. 'I need to top up my phone'

'I've got no credit left, I need to top up'

Answer

You say, that your cell phone has run out of minutes. You want to buy minutes for it or buy a pre-paid card for it. To call someone from your phone and charge it to that person's number is called "calling collect". 
I hope that helps!