I don't think its a cheap policy you want, its the ones that will pay out in the event of an incident, no point paying cheap only to cost you more if it doesn't pay out due to a small print or hidden exclusions.
I would also be very interested to know a good reputable diabetic insurance company as well, that has a history of fairness and willingness to pay out if it comes to it.
Have a look at insure and go,myself wife and daughter have just been to America in September of last Year and i paid just under £100.00 for us all, that is including the extra £14.00 they wanted to cover my High Blood pressure Cholesterol and Diabetes