It depends. Whether you owe income taxes depends not only on your wages, but on all of your income. If your gross income is below the filing threshold for your filing status, you’ll obtain a full refund as long as you file a tax return. What’s more, you may be eligible to a refundable earned income tax credit (EITC). Again, you must file a return to claim the EITC.
Interest on debt used to carry investments, but not including interest expense from a passive activity. Deductions are limited to net investment income.