I found this very recently posted on another forum and thought I would post here also for benefit of forum members if not known. I could not see where this had been posted already but I may have missed it.

"New procedure for purchasing extractors;

I am no longer selling extractors as "spares" to customers. I am a gunsmith doing repair work and not a gun parts manufacturer. The extractors that I make are labor intensive and are done on manual machines (no CNC). If you have a broken extractor, you need to send me your slide, and I will install a new extractor for you. Cost is $75.00 plus $7.00 for shipping / insurance to the lower 48 states. If you want to do your own installation, then you need to send me your broken extractor, and I will send you a replacement. Cost is $45.00 for the extractor. Sorry, but people seem to be in a panic mode about these extractors, and it almost impossible for me to keep up with the demand.
For the record, in the years that I have been servicing Sigs, I have only had 4 occasions where the pistols had damaged extractors. Two of these were due to bad reloads, one was due to a weak recoil spring, which was not holding the slide in lock long enough for the pressure to drop, thereby stressing the extractor hook, and one was a legitimate failure due to a manufacturing defect.
Regards,
Gerry
Total Automation"

If you really gotta have a spare just in case, a outfit called Matrix makes and sells them and also have a few other sig parts for their 80% frames.