Tanga offers the Post-It Flag+ Gel Pen 20-Pack in Black, Black/Yellow, or Red for $8.99 plus $4.99 for shipping. That's $0.70 per pen and the lowest total price we could find for this quantity by $2. (Several retailers charge around $5 for a single pen.) Each pen contains 50 self-adhesive flags.
5StarDeal via eBay offers the Whetstone Mini Snap Dragon Katana Letter Opener for $9.99 with free shipping. That's the lowest total price we could find by $4, although we saw it for a buck less in May. It features a 4.25" stainless steel blade, cord-wrapped handle, and hard scabbard with pink finish.