Simply go to
Inkfilling.com place your order online, and enter the following coupon at checkout for $5 off any order: GHWT3 (no restrictions, limit 1 per customer)
or
take $20 off any order over $75 with coupon: SYHW2 (not applicable to OEM cartridges, limit 1 per customer)
These end Feb 28, 2014