They say the pen is mightier than the sword but these days it is mostly the keyboard that stands in for the pen. Nevertheless antique pen collecting is growing in popularity. Many older examples are snapped up quickly but excellent selections are still available. Demonstrators (pens which were never sold to the public) and fountain pens from the early mass production period 1885-1915, (which have straight caps and taper caps) are still reasonably priced.
One avenue for pen collectors to try is to seek out lesser known names. Quality brands such as Wirt, Aikin Lambert, and John Holland have hardly been collected. Foreign brands, with the exception of Pelikan and Montblanc, have mostly been over looked. Begin building your collection by looking for quality construction, fine design, historical significance, and technical interest. It's an investment that will pay off financially and in personal enjoyment of your collection.
Most vintage pens and pencils are sold in as-is condition, so it is imperative, to closely inspect any potential pen purchase. Damage and defects seriously affect the value. A magnifier and a light are necessary equipment. Also, there is no standard grading system for vintage pens. Terms such as "good", "very good", and "excellent" can mean very different things to each seller. But as you gain experience you will see how each dealer grades and develop relationships with dealers whose grading you trust.