You shd tell your mum there is no 公價dik 禮金. My mom only got 20k from my C6 and 10k from my brother in law ja! But I can say they can pay much much more lor. My bro paid 100k to his mum in law, it was his will to give, not his mum in law asked for it. To me, 禮金 is 'sum yee'. It seems that your mum is selling daughter!