There absolutely are when it comes to materials like pens, but I bought a set of 3 pens (0.1 mm, 0.3 mm, 0.5 mm) for less than ten GBP. Specifically, Mitsubishi pencil co. unipen fine line.

Sure you can probably buy much more expensive examples, but it's not essential.

(Side note : don't try to use a gel ink pen across varnish, or it stops working until you clean it off with solvent)