The difference between contract mobiles and the free sim cards we are discussing tends to be that the monthly plans we sign up to (usually for a minimum contract of 12, 18 or 24 months) provide a free or discounted mobile handset from companies including Nokia, Motorola, Sony Ericsson amongst others. Because most of us already have one or more mobiles, it now makes sense to look at the free sim card deals too. A lot of people use the free sim cards in their older mobiles, whilst also taking advantage of the networks newer contract deals.