Recently I had to replace the tips that go into my bamboo pen. A quick search around the net led me to a few sites that wanted to charge me $20 for a set of 5 plus shipping. On Wacom's website they have tips for the Intuos at 5 for $5, but none for the Bamboo.... which is what I have.
I called them up and asked to see if the Intous tips would work in my Bamboo pen and realized that they do have Bamboo specific pen tips for sale, they just don't publish the link. A few minutes later I got an e-mail with the super secretive links and ordered my pen tips. Five of them for only $5, shipped free via priority mail!
Why they don't publish the link is beyond me, but anyway I don't see the point in not sharing it so here is the info they sent me. I have a Bamboo Pen & Touch, or the CTH-460. Don't ask me if these will work in your pen, cause I honestly don't know. If you have a Pen & touch though, they will work.
ACK20101K Bamboo Pen Nibs and Extractor black [link]
ACK20101W Bamboo Pen Nibs and Extractor - white [link]
Please contact Wacom Customer Care at 1-800-922-6613 if you have any questions.
Or if nothing else call them before you pay someone else out the ass for pen tips!