With orders of $25 or more, Amazon continues to offer Prime members the Write Dudes Infinity Metallic Permanent Marker 8-Pack in Assorted Colors for $4.64 with free shipping. That's tied with our mention from last week and at least $5 less than you'd pay at a local retail store. They're acid-free, non-toxic, and can be used on dark or light surfaces.
Note: This item is offered as part of Amazon's "add-on program" and can only be purchased with an order of $25 or more. Additionally, it currently has an estimated shipping delay of one to two months.