You can buy an Apple Bluetooth Keyboard but it will cost you more. It looks exactly like Apple Bluetooth Keyboard. It requite batteries but the package does not include any. I used two Kirkland Signature AAA batteries.
Any brand will work fine. Close the battery cover and turn it on. There is a small black button black says "Connect". On iPad side, go to setup and go to bluetooth. Make sure it is On. It detects the keyboard and ask you to type 4 numbers.
Type those 4 numbers and hit "Return".
It is that simple. Now your new keyboard is connected to your iPad. It is like having a small computer. I like it.
It was very easy and it should increase your productivity using iPad.