I'm not a finance or markets guy AT ALL, so this may not be right, but I think there are two ways to refer to the live stockmarket price - the most recent price at which shares were purchased, and the lowest offer for sale still available to buy. I think these are referred to as the "Bid price" and the "Ask price". This might explain why you see a difference; I assume the bullion retailer always quotes the Ask price, while the news would display the Bid price. Someone correct me if wrong. IIRC, there might be also some aspect about which month's "future's contract" is being referenced?
Or the difference you noticed might also be something as simple as the spot price shown on the retailer website is 5 or 10 minutes outdated, if it's too expensive for them to constantly pull the live per-second price until you start the checkout process.