incidental expense(n = noun.possession) incidental, minor expense - (frequently plural) an expense not budgeted or not specified; "he requested reimbursement of $7 for incidental expenses"
is a kind of expense

at any expense, business expense, expense, expense account, expense record, incidental, incidental music, incidental to, interest expense, lobbying expense, medical expense, minor expense, moving expense, non-cash expense, operating expense, organization expense, personal expense, promotional expense, trade expense, travel expense