Tesco currently have packs of 6 x 330ml bottles of Magners Irish Cider for £3.00 . This works out at £1.52 per litre / 86p per pint and is much cheaper than any other current offer for bottled Magners.
Just to quickly cover a few of the points that always crop up in threads about Magners:
Magners in Ireland is sold under the trade name of Bulmers (totally separate to the Bulmers in the UK). They don't have the right to the name in the UK, so sell it under the name of Magners. (thanks to gratts for this)
Many may consider Magners to be 'an overpriced mass-market fashion drink'. If you feel this way fair enough and you can move on to a deal that interests you.