This is the marriage custom in Taicang. Gifts are given back, and one is given to each family. There is nothing special about sending oil. Every wedding present is selected by the host family. There are many kinds of gifts, such as oil, blankets, quilts, four-piece sets and washing powder. These things are more practical, and they are still for food, such as biscuit gift boxes, Want Want milk and Mengniu fruit. The strangest thing I received was the underwear set for autumn and winter, divided into men and women and sizes. I really don't know what the host thinks.
In addition to the gifts from various families, the elders who give the bride and groom lucky money will receive another gift. So it costs a lot to hold a wedding in Taicang.