Idon't think there is such a thing as sugar free ham, I've looked an dlooked. I managed to find sugar free jerky at one health food store, but they wanted a small fortune fo rit.

Basicaly a product can have up to 0.9g of carbs per serving and be listed as 0. Watch serving size too as many companies will make that very small to have fat, cals, and carbs be low. 1/2 a slice of bread or 1/2 a miffin is an example (I found what I thought were moderate carb brautwursts, then I read serving was 1/2 a sausage)

Like Potato said, look for ones where dextrose is at the bottom of the list. Hopefully under heading "May contain up to 2% of the following" Also look for multiple kinds of sugars instead of just 1. (some hams are honey baked with mollassas, sugar, high fructose corn syrup and dextrose)