Ebay is a reliable site to buy from, correct?

My parents aren't very tech savvy. I understand only the basics of ebay - my parents don't understand squat. I want to buy a shirt off of ebay but I'd need my parents credit card (I will reimburse them in cash). I think my mother is vary wary of the reliability of buying from ebay. How can I convince her it's a reliable site to purchase from?