If you are looking for different online sites ther is a post in the General section titled Internet Sites, there are a bunch of different sites there with both "free" and "to buy" sites. Some in the states and some over seas. Have a look it may help you out. Also in the general section is a thread titled "Free online alphabets" also some very good sites in that thread.
I don't tend to buy online but do have quite a few of the freebies. Can't say on site is my favorite there are just tooooooooooo many with lots of fun stuff on all.
I have to say... CyberStitches has now become a fave! You'll have to download the pattern viewer (there's links to it from the site), to get all the freebies, but it's well worth it! You'll find it here: http://www.cyberstitchers.com/home.asp
There are so many sites with freebies, but I think the ones put up in the other thread are some of the best. Cyberstitchers does have some excellent freebies, and the pcstitch viewer is very easy to dowload. (If I can, then anyone can!)