Worldspreads is the self called home of 0% spreads. They are often advertised on Bloomberg (you may have seen the advertisement) and provide newcomers with up to 300 free.
To take advantage of this offer just visit world spreads.com and open an account. Then simply deposit 500 and make a couple of qualifying bets and they will credit your account with the 300.
5. ETX Capital
ETX Capital is one of my favourite platforms due to its ease of use and features. They are currently offering 250 for produtos digitais new clients if the punter loses their money. Again get yourself an account and deposit with the peace of mind that if you do lose, your loss will be credited back into your account after 10 business days.