yip........ I have 2 favourites I have used for years now.
Travel-Travel is my first stop. Good on holidays but even better on flights. This is a very last minute type place, never short of summat so hang back with confidence. I would suggest you book no more than 3 days ahead and be flexible about what you fancy.
Flightline more of the same. However, it is like they prebook batches as what one has the other more often than not, can't get.
Practice, get to know the sites so when the time comes you can track the deal you want without frustration, and know you have found all the cheapest options.
My own preference is flight only, deals on digs are easy done when you are there and holidays are priced for two.
I've done, off these sites,
Crete ?60 flight and my hotel was a tenner a night, bang on the beach.
Zante, Kos, majorca, alicante and grenoble (ski-ing) were all under ?80
HTH