The Surface Go starts at £379 for the basic model with 64GB storage and 4GB RAM. The next model up with 8GB RAM and 128GB storage costs £509, but right now you can get it off Amazon for £468.45, saving you £41.
Amazon is also bundling this model with the black Surface Go Type Cover for £586.45, which saves you £22.
It's a better deal than Microsoft's all round. Not only is Microsoft's offer on the same Surface Go model and Type Cover more expensive, at £628, it doesn't actually save you on the devices themselves. What you do save is £40 on the 1-year Office 365 subscription that's tied in (it's non-optional by the way), which isn't useful if you're already a subscriber, and of course, if you don't actually need it (there's always Google Docs).
You can see more Surface deals in our dedicated article, which has all our reviews and buying advice in one place.