Wikipedia
Blyk
Blyk is a "free" ad-supported mobile phone network that offers text messages and customer-to-customer calls. It targets young people (16-29) has offices in Finland, the Netherlands, the United Kingdom and in India.
Blyk was first launched in the UK. It was the first mobile network funded by advertising, and was targeted at 16- to 24-year-olds. Users signing up to the network received advertising messages on their mobiles, and in return were given a monthly allowance of free top-up.