Try SwiftInk.com . Be fast about changing tanks as epson has ridiculously fast-drying/fast clogging ink. These aren't the cheapest, but those who own Epsons buy a lot of ink from SI.
SI often gives ATers special deals - watch the stickies at the top of the HOT DEALS section. He also has a deal at Heatware quite often (but not as good as the deals we get).
.bh.