As far as I know, there is no custom in Wuxi for a mother-in-law to buy a son-in-law similar to "three golds". Generally speaking, "three golds" refer to gold rings, bracelets and necklaces in the traditional sense. This is a custom in some areas of China, but it is not a wedding custom in Wuxi.

In Wuxi's wedding custom, it is usually the man who buys wedding jewelry for the woman, such as gold rings and necklaces, to show his love and respect for her. In addition, the man also needs to give a certain gift to the woman's family to show his respect and gratitude to her family.

Of course, different families and cultural backgrounds may have different marriage customs. If you are in doubt about the specific marriage customs, it is recommended to consult local marriage customs experts or related people.