Cracked lens requires replacement of the whole fog light assembly - at least I was unable to find just a lens. Replacement complete fog light assembly was about $75.
To replace (on 2001+ Bugs) take out the front "grill" that the fog lights are mounted in. At each lower corner of the grill, looking at it from behind the grill (car on ramps or jacks helps), is an eared tab that you kind of have to work at to pop out. There are three push pins underneath that have to be worked out, I broke mine removing them and replaced them with screws when putting it all back together. After that the rest of the grill will pop out of the clip, the remaining tabs don't require anything but pressure.
I have a panzer plate, I didn't have to remove it.
Once the grill is out the fog lights are just 3 screws and the wiring plug.
On NB's older than approximately 2001 evidently you have to remove the entire front clip to replace a fog, 2001+ you only have to pop the grill.