Marks and spencer currently have a lot of their toys and games on 3 for the price of 2 which is a good deal itself BUT at the moment they also have 20% off home which includes toys and games so you can get :
three items at £5 each (normally £15),
pay for 2 so new total £10
less 20% of the original total (20% off £15) £3
New total £7
Bearing in mind that the free delivery code works on your BASKET total not your final total you could buy 6 items at £5 - basket total £30, eligible for free delivery less 2 free items (£10 off) less 20% (£6 off) order total £14 delivered.
Couldn't see this posted already but more info on combining the two offers - the same usually works instore when they have both offers running - fantastic for all those birthday parties the kids keep getting invited to as they have bratz, disney fairies, power rangers and doctor who stuff available.