Buying from China - Tips needed?

I would like to buy some stuff from china. they are plastic enclosures. I have taken quotation from 1 supplier. But I told another supplier about the quotation from the first supplier, and he suddenly told me that he will quote me tomorrow. Do companies in China speak to each other about their quotation? Is it good for me or Bad? Should I stop telling about names of other suppliers to new suppliers I need quotation from? Please help.