Regularly check this page for current and upcoming discounts on shirts. Don't forget that returning customers can save money by sharing a pic. Also, feel free to check around the web for Spreadshirt coupon codes.
Until March 19, 2012: Use the coupon code STPATRICK2012 to save $10 in all orders over $50.
Until December 31, 2012: Get free standard US shipping on all orders of $50 or more. Use the coupon code SHIPFREEUS when checking out. Canadian customers can save up to $9.50 on shipping on all orders of $50 or more by using the coupon code CADSHIPFREE.