I saw "to spare money" on the net, for example somewhere on CBS news. Since neither you nor bhaisahab admitted there exists such an expression I'd rather wait for more repl[STRIKE]y[/STRIKE]ies or consider "to spare money" to be wrong.
If you hunt around the net long enough, you will find some amazing constructions. Note that neither bhaisahab nor suziedqq explicity stated that it did not exist.
COCA gives no examples of
spare (verb)
money, three of
spare the money, eighteen of
spare a dime (17 of them referring directly to the song bhai mentioned, ''
Buddy/brother can you spare a dime?'), two of
spare a dollar, one of
spare a nickel and none of
spare a cent.
bhai's answer in post #2 is looking good to me.