Try edietshop.com. Has lots of great sugar free items.
I REALLY enjoy the "Calorie Control Whipped Topping Mix". I used to buy Cool Whip, but the sugar-free has fat, while the fat-free version has sugar.
The calorie control whipped topping is creamier than Cool Whip, fat-free, sugar-free, and very easy to make. Note: if you make the topping with water it is 8 calories per serving (two tablespoons; note that Cool Whip is usually 20-25 calories per two tablespoons). However, I use fat-free milk, which ups the calories to 12 per serving. I keep a big tub in the refrigerator at all times (I recently bought a case of the stuff). My wife loves it also, and has started making some Dr. Pepper floats using it.
The Bernard cake mix and cake frostings are also very good. I actually found the chocolate cake mix a bit bland, so in my cakes I use the Bernard Brownie Mix: makes a nice two layer cake (using 8 inch round pans). The frostings are all great. Again: all low calorie, mostly fat-free, no sugar, etc.
One note about edietshop: my last order I waited patiently for 8 or 9 days for my order to arrive; nothing. I then emailed them one morning. That afternoon I received an email: they had lost my order! I was told they were putting my order in the mail. Sure enough, I got it the very next day: they mailed it using an 'overnight' mail service, which must have been hideously expensive since I ordered a case of the whipped topping mix. Good service (my previous orders all went fine, and I usually got the items in 5 business days).
Here in Fort Worth (if you are in this area) you can purchase most of the foregoing items at Diabetic Design, on Beach Street about 2 miles north of 820. Great people!