Some time back Ed Davidson (YoYospin here on IAP) gave a good example for pricing. If you do a search, you will find this. You can put your own numbers (kit price, blank cost, cost for consumables), pens made per hour, overhead and profit percentages and you come to your wholesale and retail price. This is a very smart approach. I have tested it on several of my pen models and it works fine. However, I have used in the past the material cost times a factor method; and compared these numbers to the ones Ed's model comes to: pretty similar for my standard pens. It goes apart when I use this approach for pens I make from Titanium, here the amount of pens made per hour is very small and the price I come up with is way to high to get for them. If you can make 2-4 pens per hour, this is a good approach.
I generally use a multiplying factor 4-5 for my lower end, i.e. easier and faster selling pens with a lower price (and cost), and a factor of 3-4 for the higher priced pens. So far for the last five years this worked out fine for me.