In the section for business taxes where it asks for your total purchases (supplies, materials) made during the year, does that include freight costs?

You can include it in that section or you may also include it in the business expense section where it says "did you pay for any licenses, taxes, or shipping?". You can enter your freight costs at the bottom. Do not enter shipping or freight expenses you've already entered in the Purchases made during the year in the Inventory section.

Thank you for choosing TurboTax.