It depends on how you were paid. It it was all regular wages, reported on IRS form W-2, you are not required to fie a tax return. The filing threshold for wage income is $6350.
If you were paid "under the table" or got a form 1099-Misc, instead of a W-2, you are required to file a tax return. The filing threshold is only $400, for that type of income. This is because you will have to pay social security tax on that income.
