What flights were you looking at neversaynever? I recently booked my cheapest ever flight to Berlin £77 all in from LHR for the second week of Aug - I normally go FR from East Mids (cheapest I have managed with bag and card fee has been around the £85 mark) but this was way cheaper for the dates I wanted with better flight times.
For the same dates I have just looked them up and the cheapest fare on the bmi website is now £88. But for the flights I am actually travelling on (1730 out of LHR 10/8, 1100 back from TXL 14/8) it would now cost me £238 if I booked today
Which just goes to show if you see a good fare and you know you want to or need to go somewhere book it when you see it!! And as Inkjet says, if you don't like the price, go elsewhere! Had FR been cheaper no doubt I would have booked with them as normal. Its a free market and airlines price (amongst other things) according to supply and demand.
Like the stockbrokers say, fares can go up as well as down.............