We bought our son's ear hat at the park (the one on Main Street). If I remember correctly, they were $12.95 (infant size), and the embroidery cost $5. We just had the traditional embroidery done. If you wanted the fancy fonts, it was $8, I believe.
I'm not sure if child sizes or adult sizes are more, but that is what ours cost. Because we were at the park, we were able to use our AP discount on them.