If your business is a disregarded entity (sole propprietorship or single member LLC) then any entity that pays you more than $600 is a tax year is required to issue you a 1099-MISC. If they do not, that is not your problem. But you are still required to report "ALL" business income and expenses on SCH C as a physical part of your personal 1040 tax return.
If your business earned more than $400 in a tax year, then you are "REQUIRED" by law to report the income. That's because in addition to "regular" income tax, you will also pay an additional 15.3% of self-employment tax on the business income that exceeds $400 in a tax year.
So if you are filing single and your total income from all sources is say, $6000 with $1000 of self-employment income, then you are required to file a tax return and report all income from all srouces. WHile you will not pay "regular" tax on any of the income, you will pay the $15.3% self-employment tax on the self-employment income that exceeds $400.
