If you're a teacher, instructor, counselor, aide, or principal that works at least 900 hours in a school that provides K–12 education, you can deduct up to $300 in unreimbursed expenses for books, supplies, and equipment used in the classroom.
Although the deduction survived the Tax Cuts and Jobs Act signed into law on December 22, 2017, expenses above and beyond the $300 limit are no longer deductible in tax years 2018 through 2025. Prior to the tax law change, the excess qualified as a miscellaneous itemized deduction subject to the 2% limitation.