Here's how the conversation went:
GG: (smiling her cute little dimply smile) Happy Birthday, Mommy. I made you a card!
Me: Oh, thank you! It's beautiful. Should I open it up?
GG: Yep. There's a present for you inside.
Me: Oh, wow - a dollar! Thank you, honey - that was very thoughtful of you.
Pause and a big hug.
GG: (still all smiles)
I got it from my piggy bank...you can pay me back later.