I think this might actually be the cheapest, although of course this doesn't include the season pass.
Cheapest for the two season passes are £19.99 for the 2016 and 2017 at GamersPlanet (from what I can find)
Although the 2016 is slightly cheaper at Instant-Gaming, but I know some people consider that a grey reseller.
* At time of writing - 17 hours and 58 minutes left on the discount for the standalone.
The legendary fighting franchise returns with STREET FIGHTER® V! Stunning visuals depict the next generation of World Warriors in unprecedented detail, while exciting and accessible battle mechanics deliver endless fighting fun that both beginners and veterans can enjoy. Challenge your friends online, or compete for fame and glory on the Capcom Pro Tour. The path to greatness begins here: RISE UP!