Was it wrong for her to charge her?

Was it wrong for her to charge her?

“My friend watches dogs and she’s told me how much she loved mine and wanted to spend time with her if I ever needed it. I just got back from a week long vacation in California, and when I went to pick her up, she charged me $50 a night! I thought that she wouldn’t charge me because we were friends, she offered and we never discussed money.”