I 38(m) Need advice on an officemate(31f) who i consider a friend since we've been working for more than 5 years, chat daily and are amicable.

She recently went on an offshore trip to the US and I asked her to buy me a small item, its a 5oz bottle. When she got back she mentioned i owed her $X amount of money. Now here is my concerns.

1. The item cost her nothing, as its considered a basic need and was paid for by the company credit card.
2. The main reason I asked her to buy the item, was it was expensive here, I even shared the screenshot of the price when I asked her the favor. She knew what it cost from here. I also checked prices on Amazon US.
3. She mentioned the day before she gave me the item that it cost her only $X/2.
4. If i bought it from here the cost would be X 10cents. If i knew what it would cost i would have just went ahead and bought it from here.

Tbh, the amount is nothing to me, its just hard for me to evaluate moving forward how I would relate to the person? Especially since we see each other everyday. And i cant avoid her. Any advice?

Edit: I have paid her, the question is how i would relate to her moving forward, I am a bit blunt and what she did seemed to take advantage of me. I do want to keep her as a friend, sans no more asking for favors