Meta Quest VR Headset

My son (7) wants a meta quest vr headset for Christmas. I don’t know anything about gaming. What is recommended in terms of storage, 128 vs 256 vs the 500 one? 3 vs 3s? Batman edition? Can anyone please give me advice, I’m so lost! They are on sale today and I’d like to make a decision and buy today. THANKS IN ADVANCE!!!