Never assume that Amazon’s prices are always the lowest! Sometimes they are even lower than the normal trade price but in some cases they can be quite inflated.
Via the Amazon UK website, if you click on the tiny links for ‘New’ copies from other sources, you can get the reprinted hardback edition of The Spaceframe Moultons for £43.40 (Amazon’s own price is £70.90!), the softback pocket-size version for £17.95 and the hardback The F-Frame Moultons (the new reprinted edition of The Moulton Bicycle) for £25.21 (Amazon’s own price is £36.76).
The two hardbacks come straight from the publisher in Switzerland, so you can see the enormous mark-up applied further along the supply chain. All prices quoted above are as at 17th April 2015 and exclude postage but this is clearly shown on the website and is not very expensive.