12-Pack uni-ball Signo Gel Retractable Roller Ball Pen – Link 

Amazon has this marked down right now to it’s lowest ever of just $8.99.

• Uni Super ink is specially formulated to become trapped in paper, helping prevent criminal check washing and other document alteration.
• Textured grip provides superior writing comfort and control making this pen truly a pleasure to write with.
• Stylish metallic accents with a high-quality finish.
• Archival-quality, acid-free ink is quick-drying and fade- and water-resistant.
• Stainless steel, retractable tip for added convenience.