I use the Melita one-cup pour overs. They are approx $5.00 at grocery including some filters. They can make up to about 16 oz. of coffee. The Dr Drip pictured earlier appears to be a similar product. Melita makes both plastic and ceramic one-cuppers. Plastic is light and compact. They have a web site.
I have also carried concentrated cold brewed coffee. Convenient but heavier.
Stay caffeinated,
Gary
