For year of 2015, for single filing status, under age of 65, you are required to file a return if your gross income ( total ) is at least $10300 or $11850 for over age 65.
https://www.irs.gov/publications/p501/ar02.html#en_US_2015_publink1000220702- review under Table 1.2015 Filing Requirements Chart for Most Taxpayers
If somebody might claim you, you are considered as other's dependent, then review under Table 2.2015 Filing Requirements for Dependents
