The Pentel Sliccies 2 color gel ink multi pen body component in clear, orange, pink, and sky blue, for $2.55.
JetPens carries a huge range of tip sizes and colors for the Pentel Sliccies! The refills aren't expensive either - they're only $1.65 so you can pretty much get one (or two) of each! Muahahaha!
The Pentel Vicuna super smooth 2 color 0.7mm ballpoint multi pen + 0.5mm pencil body in black, clear, orange, purple, pink, sky blue, and yellow green body, for $7.01.
There are three colors of ink refills available for the Pentel Vicuna - black, blue, and red. Good for work and note taking! At $1.50 each, you can stock up for the school year!