Calculating write off expenses

You don't need a 1099-nec to report self-employment income - How do I report income from self-employment?  You can use the cash/check entry to report self-employment income that you did not get a tax form for.   

What self-employed expenses can I deduct?

You can deduct expenses that are related to the self-employment income you report on Schedule C.

Where do I enter Schedule C?

You don't need to get a 1099NEC or 1099Misc or 1099K.  Even if you did you can enter all your income as Cash.  Only the total goes to schedule C.

How to enter income from Self Employment

https://ttlc.intuit.com/community/self-employed/help/how-do-i-report-income-from-self-employment/00/26653

You really need to keep good records of your income and expenses.  How to enter self employment expenses

https://ttlc.intuit.com/community/entering-importing/help/where-do-i-enter-my-self-employment-business-expenses-like-home-office-vehicle-mileage-and-supplies/00/27109

Here is some IRS reading material……

IRS information on Self Employment

http://www.irs.gov/Businesses/Small-Businesses-&-Self-Employed/Self-Employed-Individuals-Tax-Center

Pulication 334, Tax Guide for Small Business

http://www.irs.gov/pub/irs-pdf/p334.pdf

Publication 535 Business Expenses

http://www.irs.gov/pub/irs-pdf/p535.pdf

Turbo Tax Self Employed Tax Hub
https://turbotax.intuit.com/personal-taxes/self-employment-taxes

Turbo Tax Self Employment info
https://turbotax.intuit.com/tax-tips/self-employment-taxes/beginners-tax-guide-for-the-self-employed...