What is a SIM-Free Cell Phone?

Contextually SIM-free could mean exactly that - however some phones in the US are actually "SIM free" - as in, they do not require a SIM card to work. Sprint and Verizon devices use CDMA technology rather than GSM technology and do NOT need a SIM to work. Since GSM technology is more prevalent world wide however, both Sprint and Verizon are now making "world edition phones" which include a slot for a SIM card in case the user wants to travel internationally - but this does not mean you can use that device on AT&T or T-Mobile -- it just allows you to roam on GSM networks overseas. So basically, a CDMA device with no SIM card will not work on networks like AT&T and T-Mobile, and conversely GSM devices generally do not work on networks like Verizon and Sprint. Hope this helps!  more