I use the Take and Toss type cups with lids, they are not expensive and don't have straws. Once they are around 4 years old I give them a small amount of water in a open cup and practice where to keep the cup on the table so it doesn't get knocked over. But they don't get to walk around with the open cups, it is only for when we are sitting and eating. I wouldn't even consider open cups for your age group, it will just result in a bunch of wet kids and stress for you.