Consumable office supplies are one of the clearest deductions there is. If it is an ordinary, low-cost item you use up in the course of running your business, ink, paper, pens, sticky notes, envelopes, shipping supplies, and postage, you deduct the full cost in the year you buy it.
There is a line between supplies and equipment. Supplies are inexpensive consumables you go through; equipment is longer-lasting property like a printer, a desk, or a chair. Equipment is still deductible, but it may be expensed under Section 179 or the de minimis safe harbor rather than listed as a supply. In practice, most freelancers can expense both in the year of purchase.
If a supply is used both for business and personal life, deduct only the business-use share. A ream of paper you use half for work and half for the kids' homework is deductible at 50 percent, though most people simply keep a separate stash for the business to avoid the split.
Keep the itemized receipts and file them under supplies. Because these purchases are small and frequent, they are exactly the kind of deduction that gets lost without a system, and the totals add up over a year.

