Overview: I made this pen for my brother-in-law and thought you might like to see it. For more information and supplies you can click here for a company called "Craft Supplies USA" for many wood tools and products. Making a high quality pen is inexpensive if you have access to a lathe and only takes 30-45 minutes. The blocks of material are as low as $2.00 and the hardware (the pocket clip and the actual pen with ink cartridge) can be as low as $4.00.
This picture shows the block from which you make a pen. These are some acrylic blocks. The pen I made came from a block closely resembling the top block.
These are cherry wood blanks.
Here is my finished product for my brother-in-law. I really like the acrylic blocks because they make great designs on the pen. I am sorry there are no step-by-step pictures here. I didn't have my camera while I was making it and was under a timed deadline to get out of the shop.