Can a store refuse to sell an instock item?

My husband and I were at Champs Sports Shoe store a few days ago and asked about the jordan/af1 fusions. The manager said that she had them in his size but would not sell them to him because she was saving them to buy for her boyfriend. Just for kicks and giggles he offered her $20 extra to sell to him instead! She refused. She was snotty and rude. He joked with her and asked if she was sure that her boyfriend wasn't a size 12 instead of a 13. She responded by saying "Oh no he is ALL of a 13" in a really disgusting way. I have been told that not only is it illegal for her to refuse a sale to us, but most would consider her attitude of perverseness "ual harment". I'm not trying to throw around any ual harment cards, but if refusing to sell us the shoes that she stated she had in stock is illegal, I would love to have her fired or at least demoted. Does anyone know if she had the right to refuse us the sale?