Although it may be news to you that you “have a business” (and most of the other people who get their first 1099-MISC); The IRS considers anything in box 7 of 1099-MISC to be self employment income. Enter the 1099-Misc income, at Other Common income / income from a 1099-MISC . TurboTax (TT) will complete Schedule C or C-EZ for you and allow you to deduct any expenses associated with this income. You'll also have to pay self employment tax (social security & Medicare) on any profits greater than $400. These types of payments are frequently done this way. Your "employer" is not the only one.

 The IRS also considers undocumented cash income (no W-2 or 1099-MISC), for work performed, to be self employment income. 

Enter your income at the 1099-Misc screen (even if you didn't get a 1099-misc). For details, see https://ttlc.intuit.com/questions/1901317-schedule-c-ez-net-profit-from-a-business