At Staples stores, take in your old electronics for recycling and get a coupon good for $10 off a future $30 purchase. Many items are eligible, including monitors, printers, scanners, iPods, shredders, and calculators. This promo runs through April 22, while coupon will expire on May 13.
Note: You'll need to be a Staples Rewards member (or sign up at the time of recycling). It's free to join.