Stoneyfield sells plain yogurt that I'm pretty sure has no added sugar at all in it (all milk products, though, have some amount of natural sugar). Boy, is it tart!!! I found, though, that adding some sweetened granola to it made it tolerable. Of course you can always get plain yogurt and add as much sugar as YOU want--which is probably less than manufacturers would have put in it.
I found that yogurt was much more beneficial for me than acidophillus pills, namely because the acid. pills gave me gas and the yogurt didn't and the calcium in the yogurt did more good for me than the probitotics did. The only thing is, you get tired of yogurt after a while. My suggestion to you, if you are already on the acid. pills, is to just stay on them and eat yogurt when you feel like it. Yogurt has other cultures in it besides acid. (Stoneyfield, I think, has the most of any brand), so that is always good for you, but you can get those same cultures in multi-probitotic pills like Digestive Advantage and Culturelle. I think, however, that you will find a yogurt a day is less pricey than those items, although it probably won't deliver as many cultures.