Should be zero.
If your income will be less than $14,000, the difference between 0 and 1 is $400 of withholding spread out over a year (about $8 per week). If your income will be between $14,000 and $24,000 the difference is $600, or about $11/week.
This is the most accurate calculator to see how close you will come at the end of the year, and recommend changes. https://www.irs.gov/individuals/irs-withholding-calculator
