iBall has a "graphic tablet" that allows you to use a stylus on a surface (with graph background) to allow you to draw on the computer. Recently, I purchased it less than a month ago for about 2.5 k to 2.6 k in Chennai. It is useful for this purpose... iBall also has another product (I think it is called TakeNote) which allows you to do this separately and store in its internal memory and then transfer it later to a computer... But it costs about 10k.
In eBay, I remember seeing other brands such as Genius also marketing similar products. Go to Computers & Peripherals > Input Devices > Tablet
Arun