Quality is critical. Every pen you put in someone's hand is an advertisement. It would be cheaper to bust a pen apart and pirate the parts, or even drop it in the trash, than to put a poor quality pen out. It has your name on it.
I have been doing this for over two years. I have sold to local realtors for home closings, I have sold on e Bay, I have sold wholesale by the dozen to east coast gift shops, another good venue is Yahoo classifieds, and that's a free one, but be very careful of scammers who want to send you a high-dollar check and want you to refund the change. And, of course, the check is no good.
Marketing is a bigger challenge by far than turning pens. Go to your local realtors weekly meetings. You'll have to make an appt to be on their schedule. This is free marketing to a group who will use your product and you hit a bunch of them at one time. They will use your product if you show it; they will use it as the pen that the homebuyer signs the contract with. The pen, or better, the wood box, will have to be personalized w/ the home buyer's name. Realtors are accustomed to buying their home buyers a thank you gift, so this is not out of line at all; and I guarantee, you will make sales in this venue.
But it only works locally as it must be timely to the closing. That's why I don't mind telling everyone about this mkt. It won't affect my local market.
Good luck and best regards, John K. Eaton