I'm not sure if anyone will be able to help or not, but it's worth a try anyway.
My friends and I hoped to fly to Riga from Bristol on Dec 5th, returning 8th. We found some good prices earlier in the week allowing us to go for £20 return (inc taxes). This deal seemed still available yesterday lunchtime and my friend who found the deal seemed to think it was an offer that lasted until midnight (I'm not entirely sure on that part).
When he went to book for us last night the price had risen to £90 each!
Having not booked with Ryanair before, I was wondering if the price will stay that high (or higher) as the cheap rate only applies to the first X number of people or whether it might drop again? I'm surprised it's gone up by so much so long before the flights.
A long shot I know!