Extravagance means spending too much money, or wasting money. 

Excess means too much, or more than.

It was an extravagance to spend $50,000 flying first class on a 20 minute flight.

This diamond ring costs in excess of three million dollars.

I ate to excess in the restaurant and had too many oysters.

excess 

What does it mean ?

Please help 

I didn't get it (excess)