For officemax.com, coupon code is
SAVE20 valid 12/30-1/5,
website link here. For local stores, look for the brown bag in your Sunday paper inserts, or
print an in-store coupon here. Excludes computers, HP ink, printers, monitors, tablets, Kindles, etc WAY TOO MANY TO LIST. However it is valid on SOFTWARE and most ink and virtually all supply type items.
Another way using this is to price/coupon match at Staples and ask for 20% off, this one is YMMV though.