VPN stands for Virtual Private Network. It is a way to connect your iPad to the Internet so that you can protect your data while transmitting or show that you coming from a different place/hide your location (or both).
There are a lot of companies that provide VPN service for varying fees (they have to pay for their servers). You'll just have to do research to determine which VPN service fits your requirements.
Please, what then is the data purchased for my VPN subscriber meant for. Was it to browse or replace my data provider in my country. Can one do without the other.