Bic 4 Colour Fluo 12 Pack $14.59 + Delivery ($0 Prime/ $39 Spend) @ Amazon AU

Seems like a great price for this 12 pack if you don't mind the green being replaced by fluorescent yellow. Equates to $1.22 per pen. Pack is normally $36.

A bright new twist on the beloved classic BIC 4 Colours pen. The convenient 4 Colours Fluo pen offers the traditional blue, black, and red ballpoint tips. But instead of green ink, it has a super-practical fluorescent yellow accenting pen with a slightly thicker point than regular pens - so the right tools are always at your fingertips. Grab this box of 12 and start jotting down your notes, then click the yellow button to accentuate and circle key concepts. Get the words out faster and easier with 4 ink colours in one pen. The wide round barrel design not only offers a comfortable and sensible writing implement, it is also stylishly translucent so you can check your ink levels and never run out. Whether at home, the office or at school, you’ll also never run out of reasons to use the incredibly convenient 4 Colours Fluo pen.