We bought my niece one of the big $12 princess balloons with the light in it on our first day in the park. 6 days later, it was still going strong. We flew so we couldn't take it home. My niece (who is 4) said she wanted to give it away to another little girl instead of popping it. I'm sure it lasted a couple more days after we left. They may be expensive, but they last a long time.