What is the best way to book a flight from edinburgh to bristol?
Mary, I'd book directly on the EasyJet website. They currently have flights advertised as low as £33.99 (but of course that price will increase as the flight fills up). The actual cost may be slightly higher after a few "fees" are added, but it's still a good deal. Be sure to read their "Terms & Conditions" carefully, especially related to baggage limits. Also note that they usually only allow ONE carry-on item of the approved size (and they WILL check). If your checked luggage will be over the allowed limit, you can buy extra weight (up to a maximum limit specified on the website). It's cheaper to pay for the extra weight at the time of booking, rather than at the gate. Happy travels!
Good advice from Ken, and not for the first time. As a P.S., Bristol is an international airport with surprisingly easy connections to North America, although the route may go through Amsterdam or Paris. It is convenient for the south of England and avoids Heathrow/Gatwick.