The standard price of the console in the US is $299.99, so right now you're getting all those extras for no added cost. The new 1TB variant of the Xbox Series S is up for pre-order at Amazon.
I haven't seen this bundle so low in the UK, but the listing does say there's only one left in stock, so that may be why. The official Xbox Series X price is $499 in the US and £449 in the UK.