what is the cheapest and fastest way to get to guangzhou if we are from yi wu?

The fast way is to take the flight which will take you about an hour and a half to reach.
The bus will take you about 20 hours and the ticket price is about 400 RMB.
The direct trains from Guangzhou Railway Station to your destination will take you about 17 hours and a half and the ticket price is about 327RMB for the hard sleeper.
So, in my opinion, the trains are suggested.