Is there a limit to how much I can return without a receipt?

My kid has been really into Pokemon lately, so I've spent the last few months slowly collecting Pokemon figures from Walmart. Then today, about a week before her birthday, she told me she doesn't like it anymore. Now I'm sitting on hundreds of dollars worth of stuff, which I stupidly didn't keep the receipt for. I'm hoping I can return it and buy her something else that she wants instead, but I'm not sure what they're going to say. I've returned things before and they've given me store credit, but it's never been this much stuff. What do you think?