Bitcoin is banned (well not yet) in India but owning bitcoin is legal, and to answer your question on how you could buy bitcoin in India, here is how How to buy bitcoin in India

and to answer your second question, on which price you should buy, buying in the bearish market is the most recommended if you want profits in the long run, however, you should buy only at your own risk, because even if it is a bear market, there are chances that the price would even more drop, and vice versa. On the other side, you can't tell on which price is the right price to buy, because buying bitcoin in the first place is already a good move to make.