Flight deals from the UK

I recommend, like Dan, SkyScanner, but I have a trick.

Write you location, United Kingdom, and then your destination as "EVERYWHERE". You will then see the cheapest destinations for your chosen time period. If that is "ALL YEAR" then you will see the broadest list of flight deals from the UK for the year.

I spend a lot of time searching for deals and nothing has beaten this strategy yet. As for the promotions, like BMI Friday, SkyScanner has a reliable and frequently updated feed, so it will incorporate any changes made by the host site.

Other promotional/deal opportunities include:

1. EasyJet doing £5 off promo code - just search Google to see if there any live codes at the time of booking.
2. Ryanair changes their fares every 3/4 days. We have been really lucky by going on their site just as midnight passes (GMT) on the date their current promotion end and being the first to buy fares on the new prices. On a ryanair note, get a Virgin Prepaid mastercard to save £10 of card fees per flight.
3. Groupon and LivingSocial occasionally do UK flight deals
4. Finally - and this one takes the cake for me - Subscribe to the TravelZoo newsletter - this is a fantastic tool which gives you all the weekly travel and flight promotions from the UK. We went on a trip to Malta (flights, really nice 4* hotel, breakfast and transfers included) for 4 days for £80 - offer was on TravelZoo.

Bravofly has a new find a deal section which may be of use - I was signed up to their newsletter when I booked a flight through them and occasionally get some interesting things through that.

With Find a deal you have access to the over 9 million searches performed every month on our websites in order to find the best flights: all the best offers found by our users with just one click. The more general the search criteria (greater number of arrival and/or departure cities, flexibility on travel dates) the easier it will be to find a low-cost flight.

What you need is Money Saving Expert - a very respected site in the UK for finding bargins.

I recommend these aggregator sites:

http://www.momondo.co.uk

http://www.hipmunk.com

http://www.skyscanner.net

Also check out these budget airlines:

http://www.easyjet.com/en/

http://www.ryanair.com/

http://www.jet2.com/

I use myairdeals.com and I'm happy with it.

Of course there are very useful answers already; just to add one more. It's called HolidayPirates and it also has an android app in which you can set a price range and deals will be pushed automatically to you. Or else you may subscribe to their newsletter.