You can have any pizza or marinara sauce you want as long as there is no sugar added. Hunts makes a good no sugar added Italian style spaghetti sauce that is under a dollar a can and it tastes pretty good. You can always doctor it up with spices or meat if you want. Just check the ingredients list for sugar items instead of the nutrition area because there will be some natural sugars, which is okay on the diet.
I'm not on the SBD but I found the book at a thrift store for $2.00 so I bought it. It doesn't specify exactly what sauces but you can have tomatoes, under spices and seasonings it says you can have all that contain no added sugar. Most marinara and pizza sauces add sugar. If you make your own sauce you could make it South Beach friendly.