A double-up deal from Waitrose on their Pampers nappies.
They are offering 2 for £10 (as are a number of retailers at present). However, you can combine with their PYO offers and get a further 20% off.
Example I'm using is size 2's - you get 2 x 54 nappies for £8.00 which equates to 7.4p a nappy.
Normally I'd go for the Aldi nappies which are exceptional value imo (iro 5p / nap), however, the Pampers do appear to be more absorbent so I'm treating the little turd machine this month :)