So I have been chastised by a few people for not posting this tip.
Before I buy any product or service online right before I checkout I always open up a new tab in my browser and search for a promo / coupon code. For example if I am buying shoes online at Zappos I would Google "Zappos promo code" or "Zappos coupon code"...you get the idea. At the very least I am able to find free shipping or like 10 - 20% off my purchase. Sometimes I find amazing deals. Just spend 3 - 5 minutes looking for the best one and you would have saved yourself a few bucks or more.
Let me know if it works for you. I love hearing people getting good deals :-)