There are 100 paise to the rupee. There are 24 hour banking facilities at international airports. Travellers cheques are exchangeable at most hotels, but sometimes there can be a shortage of currency for exchange in out of the way places. Travellers cheques are acceptable in sterling or American dollars. There is something of a market for US dollars on the streets, but it is illegal to exchange money except through authorised channels.
Prices vary widely.
Hotels for foreigners are often priced in US dollars, as are many of the more expensive souvenirs. Hotel shops usually have high quality goods, but with prices to match. In the bazaars and smaller shops bartering is part of the shopping experience. There is an art to this, and the unwritten rules often evade foreigners. The more touristy a place, the higher its asking prices will be, and the greater its price flexibility.