Wow, first I must say that I looked through about 20 resources to answer this question because it amazed me how the first few pages of results for related keywords didn't yield too many reputable sites, mostly forums and such. It was a very interesting exploration, as I skimmed through several first-hand accounts, and there are even sites dedicated to getting the word out that you really don't want Home Depot to cut your wood. Why?
First of all, when you go into Home Depot, while they can be helpful, how many times have you noticed that there aren't enough staff to field all of the do-it-yourself questions. Some of the people even claim that Home Depot doesn't even cut wood, but they do, while some stores appear to set a limit on how many pieces they will cut for free. The key word here is 'free' of course, and it appears that if you want wood cut by Home Depot, you also want to be prepared. Knowing the dimensions and what your expectations should be will help you immensely. 
Home Depot does much more than cut the wood, as they will also come out and install wood for certain projects like fences and railing. They have a large supply, so that means they provide volume discounts. Whether you want wood for building something on your own, you want them to cut wood and install a fence or something entirely different, they've got you covered. 
I've never had them cut wood, but I've purchased wood from them before. The only cautionary statement I would make here is that there are some mixed reviews, plenty of them, so take this into consideration if you plan on using their wood cutting services. Of course, if you trust them to do the installation or the building, then you probably trust them to cut the wood.