Extravagantly is a related term of extravagance.
As a adverb extravagantly
is with lavish expenditure or behaviour.
As a noun extravagance is
excessive or superfluous expenditure of money.
With lavish expenditure or behaviour.
Excessive or superfluous expenditure of money.
Prodigality as in extravagance of anger, love, expression, imagination, or demands.
:They spared nothing in obtaining extravagances for each other. Everything was lavish and wildly in excess. They were in love!
*:A great bargain also had been the excellent Axminster carpet which covered the floor; as, again, the arm-chair in which Bunting now sat forward, staring into the dull, small fire. In fact, that arm-chair had been an extravagance of Mrs. Bunting. She had wanted her husband to be comfortable after the day's work was done, and she had paid thirty-seven shillings for the chair.