The Microsoft Lumia 950 price in the UK slipped a little lower, now resting at £410 (the previous cheapest price point was £420). The big Lumia 950 XL actually went up a bit to £450(up from £440).
That’s on Amazon UK and it is way lower than the official price listed on the Microsoft Store – there prices start at £450 and it’s £530 for the XL model. Note that white 950 XL isn’t available (stock for that has been problematic recently).
Carphone Warehouse has the Lumia 950 in stock for £420, while the Lumia 950 XL is on pre-order for £470. Those are the SIM-free prices, With both CW and Amazon you can get a contract with a small upfront cost and £30-&Pound;35 a month, depending on the plan and model.