Could you buy applesauce?
All the ones I've seen low in sugar have artifical sweetners - and I wouldn't do that.
All that said - the formula we are using - first ingredient is sugar so though I still worry I've stopped worrying too much...
The healthiest one I can find is Fage - it comes in single serving portions of 2% milk yogurt with fruit jam on the side. It's lower in sugar than most, and no high fructose corn syrup.
But it's only 2% milk, so I still prefer their whole milk yogurt and mixing in my own fruit for LO. They are a great snack for me, though
I give him Mountain High Original Style, which is full fat and very affordable. They sell a vanilla flavor that isn't high in sugar as well as a strawberry.