I've been using Wacom tablets for 12+ years now. Dating all the way back to the Ultrapad's with the pencil thin pens they had back then. I prefer the thick rubber coated pens shipping with the latest Intuos 3 models.
$70 for a few extra nibs and a less comfortable pen (imho) is not worth it at all. You should get extra nibs with any tablet (about 3 or so).
If you plan to trace pictures (for whatever reason), you can always go to an artshop and buy some cheap flexible plastic sheets of the desired thickness and some double sided cellotape and fashion a transparent overlay yourself. That's what we used to do when the old Ultrapads shipped with transparent overlays by default and had worn down over the years with use.
Hope this helps.