If you are 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 $250 in unreimbursed expenses for books, supplies, and equipment used in the classroom.
Although the $250 deduction survived the Tax Cuts and Jobs Act signed into law on December 22, 2017, expenses above and beyond the $250 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.