This is only for discounted items, not regular priced items. There are a couple of different methods that can be used, but I’ll use the .8 that is being discussed. Basically, they will intentially price certain types of sale items and have all the prices of that type end the same way. So xx.89 indicates a regularly stocked item that is on sale, xx.88 indicates an item the store will no longer carry, xx.87 indicates an item that is not usually stocked and can not be ordered again, etc. This is just an example. The assigned meanings may be different, it has been a long time.
If we’re going to be realistic about it, a zombie apocalypse wouldn’t last too long, given that they are generally depicted with rotting flesh. So, regardless of whether they can run, you’re correct that the best bet is avoidance until the whole thing blows over.