Quoting Bow Making Mama♥:" I don't have the paper to print it on and I don't want to go out and buy a whole stack for one shirt ... [snip!] ... "I'm going to be a big brother" or "Big Brother" I think I have seen the shirts at carters and target. So i'll check there."
Oh, something like that would be really easy to make. At wal-mart you can buy a solid color shirt for really cheap and get the iron on letters and just cut and line them up then iron them on. They may even have a cute iron on graphic (teddy bear, rattle, or something) all of it can be found in the craft aisle and could be made for probably under $10.00.