Have money to burn
Definition 1 of 1
Pro Tip 1/3Non-literal
The phrase is an idiom; it doesn't mean burning actual money, but rather spending it without thinking. 
Ever since she got that promotion, she's been acting as if she has money to burn.
Pro Tip 2/3Casual Tone
Used in informal settings among friends or in relaxed conversations, not in formal or business contexts. 
Look at Mike in his designer outfit; he's got money to burn, doesn't he?
Pro Tip 3/3Possible Negativity
It can imply criticism or envy when you think someone spends money unwisely or too easily. 
Buying another car? Someone has money to burn!