I always used plain old corn starch to prevent chafing. It works great. It keeps my skin dry and reduces rub and friction. It's way, way cheaper than some other remedies and really it's best to prevent chafing whenever possible, rather than trying to ease it after the fact. I'd rather keep it from happening to start with.
Baby powder or talcum powder will also work, but I just usually use corn starch. It's not just good for cooking!