I wanted my son to have a big brother shirt, because it seems like an exciting thing to have for a two year old. I was right it was exciting, he loves the shirt-- his badge of honor. I didn't want to spend $15 or more on such a shirt, so I made one. My son picked out a black long sleeve shirt for $3, and then I used a scraps for the rest. I think it turned out well.
When he first came to see his baby sister, after a few minutes I said baby sister has a present for you. And he looked at her, and looked back like a present for me?! It was cute. Although a shirt was slight anti climatic for him, he later liked it.