Self-Employed AND Employed: Minimum Before Obligated To Pay Taxes?

I think asking this question would be easier if i provided a scenario, so here we go: Let's say I am an 18-year-old dependent who has never filed taxes before. I am self-employed as an independent contractor, but my income for the year was LESS than $400. Like, say, $300. If I became employed, what would be... show more I think asking this question would be easier if i provided a scenario, so here we go:

Let's say I am an 18-year-old dependent who has never filed taxes before. I am self-employed as an independent contractor, but my income for the year was LESS than $400. Like, say, $300. If I became employed, what would be most I could make before I would be obligated to file for taxes?
What's the run-down on identifying whether or not you need to file for taxes if you are both self-employed and employed?

I will provide additional details if it is needed to produce an accurate answer.
Thank you.
4 answers 4