Borrowing costs for Spain eased on Tuesday when it raised 4.86 billion euros ($6.32 billion) in a sale of 12- and 18-month debt, a key test of confidence amid warnings the country may need bailing out. Investors bought the 12-month bonds at a 2.823-percent rate of return, slightly down from 2.835 percent in the last comparable sale on September 18, and the 18-month bills at 3.022 percent, down from 3.072 percent.