Costco offers its members two BIC Round Stic Grip Fine Ballpoint Pen 12-Packs (24 total) in Blue or Black for $2.98 with free shipping. (Non-members pay seven cents more; there's a minimum order quantity of two packs.) That's $0.12 per pen and $2 under what you could expect to pay at a local Staples. (For further comparison, we saw 36 BIC pens for $8 last week.)
Also available are two BIC Ultra Round Stic Grip Medium Ballpoint Pen 12-Packs for $2.98 with free shipping. That's another price low, also by $2. Deals end August 3.