You can get potentially £50 in free bets with coral with two signup offers
1) Bet £5 as a new customer, get £20 in free bets
2) Bet £5 at enhanced odds of england to score against russia @5, enhanced winnings paid as free bets.
All for new customers. I asked their support line and it sounded like you shouldnt be able to do this, but I can confirm its possible as my man has just signed up to the offer.