Comment by Karawebnetwork

If I may piggyback on this, I would recommend the "Uni Jetstream 4&1 4 Color 0.5 mm Ballpoint Multi Pen + 0.5 mm Pencil". It costs only $10 and is available everywhere. It's one of those pens that has 4 buttons to change colors but this one also has a 0.5 mm pencil built in and a tiny eraser in the cap. Having the option to add color to my notes easily made them a lot easier to read, especially for code.