It is a huge marketplace, so I would expect there to be a few bad apples. Overall, I would say 70-80% of the stuff I buy does the job.
I now only ever buy from Amazon if I’m stuck for time and need it quickly / don't have 10 min to shop around.
Answer: .300
In modern times, a season batting average of .300 or higher is considered to be excellent, and an average higher than .400 a nearly unachievable goal.