Not one for me since I already have an account (new customers only), but since people are lapping up the free bets, I thought I'd post it up as it's one of the best offers out there:
"Simply register and place a £5 single bet on Football and we'll give you 5 x £5 free bets to use on any Sport - 4 to redeem online and one to use in your local Ladbrokes shop."
I've read through the T&Cs to save you the hassle, no minimum odds or play through terms. Only thing to note is that the qualifying bet MUST be on football.
May as well keep the odds short for your qualifying bet. My suggestion - Argentina vs Nigeria - Argentina and Draw (double chance) at a price of 1.09. I.e. the £5 bet would return £5.45 - looks like a sure thing to me