India Guide
Money
India's unit of currency is the rupee, usually abbreviated "Rs" and divided into a hundred paise. Almost all money is paper, with notes of 5, 10, 20, 50, 100, 500 and 1000 rupees. Coins start at 10 paise and range up to 20, 25 and 50 paise, and 1, 2 and 5 rupees. Note that it's technically illegal to take rupees in or out of India (although they are widely available at overseas forexes), so you might want to wait until you arrive before changing money.
Banknotes, especially lower denominations, can get into a terrible state. Don't accept torn banknotes, since no one else will be prepared to take them and you'll be left saddled with the things, though you can change them at the Reserve Bank of India and large branches of other big banks. Don't pass them on to beggars; they can't use them either, so it amounts to an insult.
Large denominations can also be a problem, as change is usually in short supply. Many Indian people cannot afford to keep much lying around, and you shouldn't necessarily expect shopkeepers or rickshaw-wallahs to have it (and they may – as may you – try to hold onto it if they do). Paying for your groceries with a Rs100 note will probably entail waiting for the grocer's errand boy to go off on a quest to try and change it. Larger notes – like the Rs500 note – are good for travelling with and can be changed for smaller denominations at hotels and other suitable establishments. A word of warning – the Rs500 note looks remarkably similar to the Rs100 note.