The local currency is the Kenyan Shilling, although credit cards are widely accepted in the main cities, and in most hotels throughout the country.
You can change money at the banks in most cities, although rates can vary, and you get the best exchange rate for US Dollars. You can withdraw money from ATMs in the cities using Visa cards.
Because it has such a developed tourist industry, Kenya is not the cheapest country in Africa for travellers to visit, although meals are available from £1 in a small local café up to about £50 in a top restaurant in one of the luxury resorts. Tipping is not compulsory in the country, although increasingly it is expected - particularly in the tourist restaurants, where 10% is the norm, on Safari, you should expect to tip the driver around £2 per passenger per day.
Friendly haggling is only welcome at markets and for taxi services, and you can get up to 20% off a price if you do well.