The first time Buffy went broke, it was from buying her beautiful black mare.
The second time was forking over all her gold to that pompous count in Bravil for her little house.
Alas, she just bought a pair of sigil stones and two hatred's soul arrows from her black market supplier in Bravil*, so. . . she is broke (again

).
She'll probably find a few cheap rings, little soul gems and throw them together into junk jewelry at the University altar to sell. That'll refill her coin purse quicksmart.
*PC only - not vanilla. Ungarion is her supplier. A single transcendent sigil stone (if he has one in stock) costs 10K. A single hatred's soul arrow is 1K.

oo: Needless to say, she doesn't buy much from him.