Homebrewing can be an expensive hobby!
One thing that can add up is shipping costs. To save money, I keep a running list of items that I plan to purchase. These are items that I have decided to buy but are not pressing needs. That way, when something comes up at I really do need to order, let's say ingredients for my next batch, I have a list of items to pull from to qualify for free shipping or take maximum advantage of flat rate shipping offers.
Another great way to save money is to follow along at www.homebrewfinds.com!