Cost of Goods Sold (which is inventory at the beginning of the year + purchases during the year - inventory at the end of the year) is reported on your Schedule C as an expense. For instructions, refer to the TurboTax Help article Do I need to report inventory?
To preview your Form 1040 , including the government worksheets before you file, refer to the TurboTax article How do I preview my TurboTax Online return before filing?
You will have to pay for TurboTax or register if using the free product.
Refer to the TurboTax Help article How do I preview my return in the TurboTax Desktop software?