I know you don't have a lot of time or interest in Google, but this is what I found there in a matter of minutes. It's difficult to get an exact comparison, but these numbers will give you an idea why things from China can cost less.
In December 2013, the average hourly earnings before tax for UK workers were £13.60 for men and £12.24 for women. That's about £36,600/£25,000 annually.
But China's average annual wage was 56,360 yuan (£6,690) in 2014.