Ryanair currently have £1 flights no taxes on in May - June booking until 22nd April:http://www.ryanair.com/site/EN/
If you sign up to Entropay then this gives you an instant virtual visa card which you can top up immediately (minimum £10) online. Ryanairs website recognises this card as Visa Electron which means no card admin fee so you really can get flights for £2 return!:http://www.entropay.com/
Use this website to find the cheapest day to travel. The flight offer only started this morning so Skyscanner prices are not yet 100% up to date but it gives you a rough idea of when the cheapest flight is so you can then go to the Ryanair website:http://www.skyscanner.net/month
I have used this method twice in the past one week and can confirm it works.