[gravelc]

Has anyone ever claimed it's none?

There's no simple answer to your question as it depends on many things - sequencing technology used, library prep and coverage to name a few.

Generally, it's not far from none when aligning short reads to a high-quality reference genome. Provided there's sufficient coverage and a majority of reads covering a particular nucleotide don't have a error at that position, than the correct answer will be given. Errors creep in due to things like systemic errors in library prep (such as a PCR error), and very low coverage over particular loci due to weird AT/GC content, meaning errors are harder to correct for. Repetitive regions can cause issues for short read alignment too, but coding regions generally aren't that repetitive.

$200 is very cheap for WGS - guessing it would be at the low end of the accuracy range, as they can't be sequencing to great depth (presumably).

[klmr]

They sequence at 30x using BGI technology. Meaning: They provide the current offer at a loss.