I recently bought two ink bottles - and I think, the contents will last for a while. Pelikan sells two of their 4001 inks in XL (1000mL) - royal blue and brilliant black. In addition, these bottles are cheap. With 20-25 USD per bottle, no complaints from me. But it seems, that you can only get them in Germany. If you prefer other colours (in L = 250ml), than you need to look at e.g. Octopus ink (also from Germany). You can get 15 colors, see colour chart below. I guess they will add more colours, there is no orange yet. Buying ink should be over now, I will run out of life before running out of ink. No more buying of 30ml bottles for 10-20 USD (fingers crossed). Edit 2019/1/21 Some of the colors (10 of 15) have been reviewed on FPN (Fountain Pen Network): Burgunder, Flieder, Karamell, Karibiki, Koenigsblau, Pinie, Purpur, Rot, Tiefgruen und Schwarz. Edit 2024/7/16 Octopus has a lot more inks nowadays. Link to Octopus inks .