Amazon has Sharpie 27145 Pocket Highlighters, Chisel Tip, Assorted Colors, 12-Count for $4.97 (Reg $12.86) with free shipping on orders over $25.
The specially formulated Smear Guard ink protects your work as you highlight over most pen and marker inks, as long as you wait for them to dry first. Plus, these slender highlighters fit easily in pockets and bags, allowing you to take your Sharpie highlighters everywhere. With a sturdy chisel tip, these highlighters clearly highlight important words or underline sections of text.