To be honest, you should be able to put any art paper through most Epsons. So if you buy regular art paper (watercolour and etching papers will be acid-free and archival) it's probably a lot cheaper than branded stuff for the printer.
I use a variety of watercolour papers in my Epson r1900 including Fabriano, Daler Rowney, Arches, and Somerset. I just cut or tear to the right size.
