The only answer that I can give, is try eBay for price, quality, quantity.
I wanted a CISS for my Epson R220. Looked on eBay and got a brand new pre-filled unit for £9.99 (usually £19.99 plus) as a winning bid. The same people offered large bottle supplies of individual inks at very reasonable prices.
I believe pigment inks are the best, but I stand to be corrected if wrong.