Cartridges or bottled ink — which should I use?

Cartridges for convenience and travel; bottles for cost, color range, and the ritual. A cartridge costs roughly fifty cents per milliliter — bottled ink runs a fifth of that, in thousands of colors instead of a dozen.

The practical answer for most people: start on the included cartridge, and when you find yourself wanting a specific color, buy a converter and one bottle. That $10 step is where the hobby actually begins.