Type of Deduction:
Above-the-line tax deduction (you don't need to itemize).
If you are a teacher, and you paid for classroom supplies and other materials out of your own pocket, then you can claim those expenses as a tax deduction.
You can claim up to $250 of classroom expenses for supplies, materials, books, software, and so forth. If both you and your spouse are educators, you can both claim up to $250 of expenses for $500 total on a joint return. Any classroom expenses in excess of these limits can be deducted as an employee business expense, which is a miscellaneous itemized deduction subject to threshold of 2% of adjusted gross income.
You are a teacher, aide, instructor, counselor, or principal, and worked in a school at least 900 hours during the school year. Only grade school and high school educators qualify (kindergarten through 12th grade).
Deduction Available Until 2013:
The Educator Expense deduction is available for the years 2002 through the year 2013.
From the IRS:
"If you are an eligible educator, you can deduct from gross income a portion of your qualified expenses. You can deduct these expenses even if you do not itemize deductions on Form 1040, Schedule A. This deduction is for expenses paid or incurred during the tax year. Previously, these expenses were deductible only as a miscellaneous itemized deduction subject to the 2% of adjusted gross income limit." (Educator Expense Deduction, Tax Topic 458)
The deduction for educator expenses is found in Internal Revenue Code Section 62(a)(2)(D) and Section 62(d)(1).