refills for Bic 4-color pen?

In theory this pen is refillable, and I remember in the 1980s there
were plenty of cheap refills for it that came in a box, each box
containing perhaps a 100 or so. I no longer see those boxes. Now either
it's almost impossible to find them, or if found, it's a little sachet
containing one refill.

Does anyone know where online I can find cheap refills for this pen?
Perhaps preferably ebay? Thanks.

Try

www.bicrefills.com

I think you can order packs of 24.

Desirider.