The price of 0W and 40W is not very close, the average is about 25 yuan.It's a price of about 10 yuan.
The difference between 30W and 40W is usually 10 yuan to 18 yuan.I hope my answer will help you
I know the wholesale price of 40 watts is about 6 yuan. The price difference between 30 watts and 40 watts is small
