This post will give you the easiest way to check your Vodafone prepaid data Usage. I did browse through some forums and sites, but I didn't direct steps to check my data usage. Here I am listing down the steps which I am using to check my Vodafone data balance.

Step 1: Dial *111# on your mobile
Step 2: Enter 6 (Data plan)
Step 3: Select 1 to know your active data plans. Or select 2 to know your usage allowances.

There is also this number *121# which will help you to know about the best offers for you.
Dial *121# on your Vodafone mobile and then select interesting offers. We get huge discounts on most of the packs. I have activated a 2G net pack for just Rs. 10. Usually this pack costs us Rs. 98. Similarly there are some bonus cards which usually costs Rs. 69 but you get them for Rs. 20 or 30. Choose the best offers which matches you and enjoy..
Will update more if I find new tips.. Stay tuned. :)