Collocations for extravagant - adj.

be, feel, seem
I go to that restaurant for lunch if I'm feeling extravagant.

become

particularly, very, wildly
He had a wildly extravagant lifestyle.

rather, somewhat
a little, slightly, etc.

with
You mustn't be so extravagant with other people's money.

Extravagant is used with these nouns:
claim, display, gesture, lifestyle, praise, taste