25% off on the £27 Mix and Match 1100 plan. Contract is for 18 months.
Although it shows £20.25, that is with VAT at 17.5% so while it is at 15% it will cost £19.82.
If you use Quidco, then it should work out to £16.35 per month for the 18 months.
The handsets this deal is available for are:
Samsung - L770 (Pink); U900 (Soul Pink)
Nokia - 6600 (Fold, Black); 6500 (Slide, Silver); 6500 (Slide, Black)
Sony Ericsson - Z750i (Pink)