If you're in the market for an e-reader - but don't want to splash out hundreds on a tablet, you may find luck through Amazon's slightly more affordable kindle.
The first generation kindle device hit the US in 2007 for an eye-watering, £279 - today, you can bag one for around £50, and it's a lot more portable, ideal for on-the-go use, and slipping into your pocket.
There are four models on the market - including the Paperwhite and Fire 7 - the generations range from standard e-readers to all-round tablets with integrated cameras and on-demand TV channels.
The most popular retailers are Amazon.co.uk, Currys and eBay.co.uk for second-hand or refurbished ones. Scroll through for a full breakdown of the four types of Kindles and the best deals.
5 best deals on the Amazon Kindle
All-New Kindle Paperwhite, 6", built in light and Wi-Fi, £87.99
Fire HD 6, 6" HD Display, Wi-Fi, 8 GB (Black), £99.99
Kindle, 6" Glare-Free Touchscreen Display, Wi-Fi e-reader, £47.99
Fire HD 8" Tablet - 8 GB, Black, £129.99
1. Original Kindle
This is Amazon's best-selling standard e-reader. Its most recent model features touchscreen technology, Wi-Fi, glare-free, and a four-week battery life. Like previous versions of the e-reader, it uses e-ink technology and has a 6'' screen.
You can buy the Kindle, 6" e-reader for £47.99 on Amazon UK.
2. Kindle Paperwhite
Amazon's Kindle Paperwhite is the advanced version of the standard Kindle - with an inbuilt light, for reading in the dark.
The Paperwhite's battery life is also pretty impressive and can last up to two months.
You can get the most-recent Paperwhite for £87.99 on Amazon (Wi-Fi only). The dual Paperwhite, with both Wi-Fi and 3G is £87.99.
3. Kindle Voyage
This 2014 device features an impressive pixel density of 300ppi compared to the Paperwhite's 212. It comes in both 3G and Wi-Fi - however, the dual version costs around £60 more.
The Voyage tablet also includes PagePress - a function which allows you to turn the page without lifting a finger.
The downside? Battery life is limited to two-weeks max.
You can buy the All-New Kindle Voyage for £135.99 on Amazon, or £229.99 3G.
4. Fire HD 6 tablet
Amazon's latest generation of flagship e-readers feature in-built on demand TV, apps and all the standard features of a modern tablet.
The pocket-sized HD 6 boasts a smaller profile, 'fast quad-core processor' with front and rear cameras, and access to the app store.
Battery life is eight-hours mixed use, or 10-hours when reading, it also features Dolby Audio, a built in microphone and up to 16GB storage.
You can currently buy the new Fire HD 6 for £99.99 on Amazon.
5. Fire 7 Tablet
The 2015 Kindle Fire 7 is an all-round tablet, and can be used to watch films, read books and browse the web.
Amazon says it has double the speed of the previous-generation Fire HD 6, with faster app launching times, smoother and richer games and videos, and ''better overall performance''.
The Fire 7 is a pocket-sized 7'' tablet with front and rear cameras and Firefly - a database with over 90 million movies and TV episodes, audiobooks and songs.
It also comes in 10 colours, and is available in 8 or 16GB. battery life is slightly less compared to the H6 6, at eight-hours mixed use, or nine-hours when reading.
You can currently buy the Fire 7 Tablet for £49.95 at John Lewis.
6. Kindle Fire HDX
The 2015 HDX display brings together almost perfect colour accuracy (100% sRGB), reduced glare and improved brightness for a clearer viewing experience.
What is HDX? The display features over 2million pixels for vivid, lifelike images that go beyond standard HD.
Kindle Fire HDX tablets are powered by the 2.2 GHz quad-core Snapdragon 800 processor. Combined with 2 GB of RAM, Amazon say they offer faster app launches, faster website loading times, smoother multi-tasking and better overall performance than previous generations.
Battery life exceeds 11-hours when mixing reading with surfing the web or watching TV shows. Just reading, battery life extends to 17-hours.
Both the 7" and 8.9" Kindle Fire HDX tablets have a front-facing 720p HD camera and 4G speeds.
You can currently purchase the HD7 7 tablet for £149.99 on the eBay Argos outlet.
7. Fire HDX 8.9
The Fire HDX 8.9 merges performance with a 2.5 GHz quad-core processor, faster Wi-Fi and stereo sound with Dolby Audio.
With a built in high-resolution 8MP rear-facing camera, plus a front-facing HD camera, you can capture high quality photos, shoot 1080p video and connect with HD video calls.
Also included is Amazon's new ASAP tool (Advanced Streaming and Prediction) which learns what movies and shows you like and gets them ready for you to watch.
The more you view videos on your Fire tablet, the more accurate ASAP becomes, dynamically adapting to your viewing habits.
Battery life is 11-hours mixed use, or 18-hours when reading.
You can currently buy the Fire HDXX 8.9'' for £329.99 on Amazon.
Where can I buy a refurbished Kindle?
If you want to save even more money, you can buy a refurbished Kindle online for around a third off the RRP.
The eBay Argos Outlet is a good place to start, as is the Tesco eBay Outlet. If you're quick, and can handle an auction, eBay.co.uk is a good place to start too. See our guide on how to win an eBay auction here.
Other sites to try include Preloved and of course the Amazon Warehouse. You can also keep an eye on our eBay deals page for the best Kindle voucher codes.
How can I spot Kindle sales before everyone else?
For sales news, keep an eye on the Amazon Lightning Deals page, or our Amazon voucher codes guide here.
Currys PC World also occasionally hosts Kindle sales, but you'll have to be quick, as they sell out fast. Voucher code websites like VoucherBox are also worth keeping an eye on.
For more tech sales, tips and tricks, keep an eye on our tech deals page, or to see our round up of the best iPads on the market, see our deals guide here.