Tanishq, Caratlane (owned by Tanishq ) , Bluestone are 3 best options for online. You can find all details like Gold weight , Rate of gold depending on Carat - 22/18 , making charges - Rs/gm And taxes 3% . None of them ask for any delivery charges .
Do check estimated delivery time - should be less than a week if product is from ready stock .If it made to order then delivery time could be 2-3 weeks .
If you didn't have the constraints of buying online i would have suggested to buy from a reputed store in your city . It's better and cheaper - buying jewelry from these online stores will always cost you more .
P.S. - I have a small jewellery shop and we deal in gold & diamond jewelry. You can DM me if you have more queries.