I have just downloaded kindle on my iPad Air but when I try to buy a book from amazon, it says it won't allow it on my device, any suggestions

Have you linked it to your Amazon account?

No and I wouldn't know where to start

https://www.youtube.com/watch?v=n3R5qBjOvkA

I had already done that and still nothing, I have the latest iOS 7.2

So is the Kindle app registered? Can you see your name under settings?

You're not trying to get 'loan' books as part of Prime are you?

You're buying books through the Amazon website right? Don't think you can buy through the app as Apple will want a cut.

Yes as ive noticed, but last night I came across iBooks so I am happy

Like the other the previous poster said, i do not think you can do it directly. But you can use Safari to buy on the Kindle shop and send it directly to the app.

Yes, once you've bought Kindle books from Amazon and logged into the Kindle app, your purchases appear as "cloud" items and you can then download to your iPad.

Surely the logic of paying 30% to Apple and another x% to Amazon for books shows why it won't work.

It is not a sane way to do business for many a reseller.The same applies to music resellers.

You've done exactly what Apple want you to do. They impose this totally artifical restriction on apps to make buying direct from Apple themselves much easier.

Basically anything bought through a 3rd party app, Apple consider an in-app purchase and want a 30% share of the retail price (note not 30% of the profit).

The way around it is to exit the app and make the purchase direct from the vendors website, then go back into the app for your purchase to be visible. Obviously this is a hassle for many people. So quite a few just buy the book or music or whatever direct from apple themselves to avoid this.

It's a totally anti-competitive practice, but Apple seem to get away with it by keeping very tight restrictions on their Eco-system.

Glad you found a solution, one thing I would say to keep in mind, in future whatever device you buy you can download the Kindle app and have access to all your books, iBooks will always be a Apple only thing.