Occasions on which brands offer 0% making charges

I'm planning to gift my mom some gold jewellery this year(first time buying jewellery), as a token of love. Would be ideal if I can save up on the making charges. Are there any particular occasions during which brands offer 0% making charges? I've seen that on Bhima every now and then but I'm more inclined towards Senco or Tanishq because of their designs.

Would be very grateful for your input.