Do you want something to get the word out of your business? Printing you own custom T-shirts is a great a business tool. You can let your satisfied customers advertise for you at surprisingly low rates with free or low-cost shirts that bear your business name on them.
Hint: people are more likely to wear your shirt if it's tasteful. Most people prefer a little image on the upper left chest and a larger image on the back, rather than a large image across the front. The more they wear them, the more exposure for you.