Anonymous wrote:How old is your son? 3, 4, 5? Kids that age can change their minds pretty fast. I think I'd tell him that I wanted to get some pictures of him playing in the car before we told Grandma that he wanted something else. Sometimes playing with a toy in a totally different environment can be a big difference. You (and he) might be surprised to see that he actually enjoys his car at home.
Bingo! This post is right. Tell him it's a gift and was given in kindness and thoughtfulness (grandma could never have known he was "tired" of the coolest new thing
already!). Have him play with it at least some and do send her pictures. He might indeed get into it again.
Invite some of his friends over for playdates and they might be into it and thus he might get renewed interest.
If he plays with it even a bit, then I can see selling it later on after he's had a while to try it out with encouragement -- but selling it almost immediately after he gets it seems, as someone else posted, mercenary; it smacks of converting things to cash while they're still trendy and it seems like telling a kid "Sure, you can always get exactly what you want, when you want it."
Also, others say to ask her for the receipt but that's a risk-- if she doesn't have it she's going to feel so flustered when you ask, and then possibly be upset with herself for not hanging onto the receipt if she didn't have it. Why put a gift-giver in that awkward position? Not polite.