Large-screened devices such as tablets and foldables often work better with Bluetooth keyboards. Improve your productivity by investing in a lightweight keyboard that's compatible with your Android phone or tablet. There are plenty of leftover Black Friday deals as well as delicious new Cyber Monday offers on keyboards, with prices starting as low as $9 for some.

The affordable Anker Compact Wireless Keyboard is the star of the show. Priced down to a mere $8.79 on Amazon, this compact keyboard can be connected to three devices at once and has a folding stand built-in. You can use it with smartphones and tablets as well as laptops and computers.

Anker's products are always great, and the battery-powered Compact Wireless Keyboard is just as good, complete with an 18-month warranty from the brand. You do need two AAA batteries to run the keyboard, but happily, Anker includes them in the box.

If you're looking for something that works with Chrome OS, Logitech's excellent K400 Plus and K480 keyboards are both on sale for Black Friday and Cyber Monday. They're around $20 each though, which isn't anywhere near as cheap as the Anker keyboard. However, finding Bluetooth keyboards that work with Chromebooks is tough, especially with a tight budget in mind.

Meanwhile, the unique Seenda Foldable Bluetooth Keyboard is also on sale, with a 30% reduction in its retail price. This intriguing Android keyboard works with various platforms including iOS and Windows, but not Chrome OS. You can fold it up neatly and tuck it away, and it even has a touchpad built into it. So if you want an alternative versatile keyboard, check out the Seenda Foldable Bluetooth Keyboard which is on sale for only $27.99 on Amazon.