Lothian Buses is the main operator within Edinburgh. You can buy tickets on the bus. The Bargain Day Ticket (£2.30), allowing unlimited one-day travel on the city's buses, can be purchased in advance or from the driver on any Lothian bus (exact fare is required when purchasing on a bus). The Rider Card (for which you will need a photo) is valid on all buses for seven days (Sunday through Saturday night) and costs £12; the four-week Rider costs £36.
Lothian Buses (Waverley Bridge, Old Town. 0131/555-6363. www.lothianbuses.co.uk).