Is there any other airline besides Ryanair that has a cheap flight in late August? I have never flown Ryanair and I would like to know if it's a good way to go or not?
RyanAir is not bad at all as long as you read the rules and weight limitations on their website. Lots of "gothas" for extra pounds (Great Britain Dollars). Also, RyanAir does not fly to Rome. It flies to nearby Ciampino. You then take a bus for an hour or so into Rome. Still the value is there if you book early and pack light.
You might want to know that www.flyglobespan.com is a budget airline that flies from Edinburgh to Rome.
My only flight on Ryanair (London Stansted-Cork) was fine for a budget airline. Be sure you observe the luggage size and weight limits. It will cost you if you don't. Most important, observe Ryanair's strict check-in deadline. If you don't have a boarding pass in hand when that deadline arrives, your ticket will be worthless and you'll have to buy a full fare ticket on a later flight. (This is true for all budget airlines.)