Depends on the use, of course. But, if your kid likes to have it turn on, let's say, a couple hours at day, then the batteries will get discharged in one week. Could sounds like I'm over reacting, but this toy, which is terrific, needs actually four batteries AA per week. Good luck anyway!
I don't know because I use the batteries. I've been thinking about purchasing one but I'm not sure because I have already spent close to 200 follars between the rubber case, carrying case and apps. I do agree with the previous comments about 4 batteries a week when played with a lot. Maybe buying rechargeable batteries is a better idea.
We use the Leapfrog Battery kit and charger, If I Ha to buy batteries for this it would cost a fortune,. A Full charge gives a Full 5-6 hours of playtime. And it is in Constant use ! Well worth the investment. your Kids WILL use this ! My 17 Month Old Will spend an Our on it in her Playpen With Feet up in the air and the Pad resting on her shins. My 5 Year old (The Intended owner) will spend 2-3 hours a day sometimes and often takes it to bed !
My boys needed new batteries every other day for the firs few weeks. Now they go through a set of batteries in a weekend. I invested in the chargers because I was going through batteries like crazy. We just went on a trip that was about six hours in the car and they were on non-stop all the way there. We needed new batteries on the way home so I'd say about 6-8 hours in batteries not really sure about the charger yet.