The number of negative feedbacks is less important than the percentage.
One neg out of ten transactions ( or 300 out of 3000) is terrible and the seller will probably be restricted or booted.
One neg out of 10,000 (or 300 out of 300,000) is acceptable since a small percentage of buyers of anything suffer buyer's remorse, or had a fight with the spouse, or a tummyache, or need their meds recalibrated. Plus there may have been a few bad transactions in those 300,000.
A feedback percentage of less than 98% is a pink flag. Of less than 95% is a red flag.
But read the negative feedbacks. They may make a real problem evident (for example, everyone is complaining about poor packaging or slow shipping) or be a scattergun of oddities.
