Yes you probably should send in an estimated payment if you know you have a Net Profit for the year.
Here are the blank estimate forms and instructions for federal. You need to go to your state's website to get theirs.
https://www.irs.gov/pub/irs-pdf/f1040es.pdf
Or you can pay directly on the IRS website https://www.irs.gov/payments
Be sure to pick the right kind of payment and year.....2019 Estimate
The 1040ES quarterly estimates are due April 15, 2019, June 17, Sept 16 and Jan 15, 2020. Your state will also have their own estimate forms.
Some general info on self employment............
To report your self employment income you will fill out schedule C in your personal 1040 tax return and pay SE self employment Tax. You will need to use the Online Self Employed version or any Desktop program but the Desktop Home & Business version will have the most help.
For the future, There is also QuickBooks Self Employment bundle you can check out which includes one Turbo Tax Online Self Employed return....
http://quickbooks.intuit.com/self-employed
You need to report all your income even if you don't get a 1099Misc. You use your own records. You are considered self employed and have to fill out a schedule C for business income. You use your own name, address and ssn or business name and EIN if you have one. You should say you use the Cash Accounting Method and all income is At Risk.
After it asks if you received any 1099Misc it will ask if you had any income not reported on a 1099Misc. You should be keeping your own records. Just go through the interview and answer the questions. Then you will enter your expenses.
Self Employment tax (Scheduled SE) is automatically generated if a person has $400 or more of net profit from self-employment. You pay 15.3% SE tax on 92.35% of your Net Profit greater than $400. The 15.3% self employed SE Tax is to pay both the employer part and employee part of Social Security and Medicare. So you get social security credit for it when you retire. You do get to take off the 50% ER portion of the SE tax as an adjustment on 1040 Schedule 1 line 27 (goes to 1040 line 7). The SE tax is already included in your tax due or reduced your refund. It is on the 1040 Schedule 4 line 57 (goes to 1040 line 14). The SE tax is in addition to your regular income tax on the net profit.
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
