Are you trying to file your states sales tax report ? TurboTax does not do that
Are you trying to file your own income return including your income from sole-proprietor business ( schedule-C ) --- you will have to upgrade -- I do not believe the free version supports that feature.
Gross Income --- $500
Cost of Goods Sold ---- $400
Net Profit before Taxes & expenses --$100.
Note though, this is not your real profit --- you have to allocate all the other expenses ( both fixed such as rental of the building, equipment, labor etc. etc. AND variable such as postage, delivery etc. etc. ). Only after that you get your real business profit before taxes. That is what you pay taxes on -- Federal, Sate and Self-Employment ( 15.3% )
Does that help ?.
Thus you net at that point is $12,000. You still have to show all the other expenses including PayPal fees.
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. The SE tax is already included in your tax due or reduced your refund. It is on the 1040 Schedule 4 line 57 which goes to 1040 line 14. The SE tax is in addition to your regular income tax on the net profit.