callingshotgun@callingshotgun These exact colors aren't available outside of these gift boxes, but the 30ml plastic Diamine bottles are $7.50 (USD) each. You can try to match similar colors and make your own set, but this drop is a good discount even with tax and shipping (averages just under $8 a bottle for me).
toomanypensSo you basically get the nice box "for free" here. This box isn't simply a piece of junky cardboard.
Also also, in the USA you don't have to pay import taxes on your purchase like you would if you bought them from, say, CultPens in the UK. It's a small but non-trivial amount.
ScottayThe refills are actually sold in small plastic refill bottles by Anderson Pens, Cult Pens, and directly from Diamine, as well as from some other sellers - just FYI for anyone considering these sets. (Just make sure you keep the glass bottle in the sets to refill.)