Everything you receive of value is considered taxable income, including gift cards or barter items (using the fair market value). The question is whether this is hobby income, or self-employment. There are some tests listed here.
https://www.irs.gov/newsroom/hobby-or-business-heres-what-to-know-about-that-side-hustle
https://turbotax.intuit.com/tax-tips/small-business-taxes/when-the-irs-classifies-your-business-as-a...
If it is a hobby, you report the income as hobby income, including the value of gift cards, and including money or gifts that are not included on a 1099-K. You can't deduct expenses, but you don't pay self-employment tax, just income tax. If it is a side business, you report all income (even if it is not on a form), you can deduct expenses (if you have any) and you pay income tax and self-employment tax.
