For all journeys from 16 May 2016 onwards Virgin Trains East Coast are offering a free WiFi code if you book your tickets direct. This is only in standard class as WiFi is free to all in first class. If you've booked your tickets already you should still receive a WiFi code via email. This only applies if you book your tickets direct on virgintrainseastcoast.com
Some business travel agents also have a deal where you can get free WiFi in standard class so if your company forces you to book through a travel management agency it's worth checking with them if they have a deal with Virgin Trains East Coast for free WiFi.
The plan is eventually to make WiFi free to everyone but first of all they need to be confident that their systems can cope with the demand. Limiting free WiFi to those who book direct means they can scale up the number of users gradually while providing an incentive for booking direct (as Nectar is not an incentive).
Before East Coast Rewards was scrapped you could use your points to buy WiFi access, it was just 50 points for a days WiFi pass. This meant those in the know could have free WiFi for most of their journeys just by using some of their points. Once East Coast Rewards was scrapped the only option was to pay £9.95 if you wanted WiFi for your full journey, it was not possible to redeem Nectar points or Flying Club miles for WiFi access.
So now I'm looking forward to being able to use WiFi for the whole of my journey when travelling in standard. I never paid for WiFi as I thought £9.95 was quite expensive considering WiFi on the train can be quite slow and patchy.