There is the commonly used "De nada".
Which translates to 'It's nothing.'
There is the much less common "Por nada".
Which translates to 'For nothing'.
And there is the common, more polite way; 'No hay de qué'
Which is used like 'Nothing to thank me for', but translates directly to english clumsily.
And finally, there is also 'a la orden'
Which means that you are at their service and will help the person further if they wish you to.
