Comment on BTST/ATST( Buy/Acquire Today Sell tomorrow)
Yes Mani,
You can place limit buy or sell orders to choose the price at which you want to buy or sell. To buy you will need money and to sell you will need shares in your demat account. http://www.zerodha.com/z-connect/blog/view/orders-place-modify-cancel-view
You can also place after market orders in the evening, if you don’t have access to place orders during the market hours. http://www.zerodha.com/z-connect/blog/view/pre-marketpost-marketafter-market-orders
But all orders you place get cancelled at the end of the day, so you will have to place it once again after that.