If you’re looking to replace old insert bits or need new sizes, check out these currently discounted bit sets on Amazon.
PB Swiss 10-Piece Set – There’s very little information about this set available, but according to this source, the CA6-972/C6-972 model number refers to a 10-piece Torx bit set. 10 PB Swiss Torx bits for $8 is a pretty good deal.
(Update: see comment #1, apparently these aren’t Torx bits after all.)
Wera 30pc Bit Set with Rapidaptor – Seeing as how a Rapidaptor bit holder is about $12 itself, the Bit Check’s $21 price is a bargain. Personally, I would only ever use maybe half the bits, but the Rapidaptor and handy case make the deal hard to refuse. Here’s a list of included bits.