pocket money
Also, spending money. Cash for incidental or minor expenses, as in They don't believe in giving the children pocket money without asking them to do chores, or Can I borrow a dollar? I'm out of all my spending money. The first term, dating from the early 1600s, alludes to keeping small sums in one's pocket; the second alludes to money that may be spent (as opposed to saved) and dates from the late 1500s.