I used to buy these bags from Amazon. They cost £3.99 for 20, with free standard delivery or free next day delivery with Prime. I was very happy with the product and all was well.
I could now buy the same bags through Amazon at the same price: £3.99. One little difference, though. The supplier is no longer Amazon but is Simplehuman. And Simplehuman adds £4.99 postage and packing to the order price. Result: 125% price increase. The Amazon price is no longer competitive; in fact, you can order at the same price direct from Simplehuman.