Go to https://www.irs.gov/pub/irs-pdf/...u00a0 You will file a form 1040ES each quarter.u00a0 The website will tell you the due dates for each quarterly payment.u00a0 Get a similar form from your state tax board website if you pay state taxes.Note: If this is your first year filing, ever, then you can get away without sending in estimated payments because you owe the LESSER of what you owe this year or last year.u00a0 Having been self-employed most of my life, I always filed quarterly estimated taxes, using the amount I had owed the year before, because I had to to avoid fines, and because I didn't want to get to April of the next year and not have the money.u00a0 As for the amount you should pay to the IRS and your state, you might be able to figure this out using worksheets available on the IRS and state websites.u00a0 If you chose to deal in cash and not report it, that's your business.u00a0 Your students are not going to send you a 1099 at the end of the year.u00a0 But if you teach at an institution which pays you more than a few thousand dollars a year, they WILL file a 1099 stating how much they paid you in miscellaneous income, with the IRS and state.