It makes an Amazon Prime subscription all the more tempting as you also get music streaming thrown in (typically £6 per month elsewhere) and fast delivery when you order physical products from Amazon, as well as several other perks. You can find out more about Amazon Prime by clicking here.
You'll need a subscription to Prime Instant Video (sign up for the free 30-day trial here) plus a tablet or phone to download videos. Supported devices include Amazon's own Fire hardware, all Android devices and an iPhone or iPad.
Once downloaded, you'll need to launch the app and log in with your Amazon details.
You'll now see all of the TV shows and Movies available from Amazon. Be warned that not all instant videos are part of your Prime subscription. Look out for the Prime banner in the top right corner of the show's image to make sure you won't be charged extra to watch.
Not every video is available to download, but it's easy to see which are. Click a show or movie you'd like to watch and look for the download button.
If it's a TV show, the download button is a downwards arrow situated next to the play button on each episode. If it's a movie, the download button is just below the green 'Watch Now'.
Tap the button to start the download. You'll want to be connected to WiFi as this will use a fair bit of data. Downloading an episode or movie can take quite a while too, so make sure you give yourself plenty of time.
Once downloaded, you'll be able to find your movies and TV shows in the downloads section of the app. Use the tabs at the top of the downloads section to switch between your movies and your TV shows.
Simply press play to start watching, even if you're not connected to the internet.