Listed below this text are some resources which may be helpful to you. I am only listing the free resources because everyone knows about Ancestry.com. It is an excellent place for your research. Indeed I got probably 75% of what I have through Ancesty.com. But since they are well advertised, I see no need to include them in this list.
You may have heard of some of these and maybe you didn't dig deep enough and crossed them off your list. I did that with some sites before but wound up back there and found new resources. If you have any good free resources that you have found and that are not on this list, please use this Contact link to let me know what they are and the Internet address for them. Happy researching.
This site has always been run by volunteers. They have a separate site for each state and then they have one for all of the U.S. Most, if not all of the state USGenWeb sites also have cemetery listings which consists of volunteers physically walking the cemeteries and writing down the infomration on each and every grave marker. Some are so old they are illegible but most of them are readable. Many of these cemetery sites also have photos of grave markers etc. It is a bit tedious if you are not certain which cemetery an ancestor might be buried in, but it is a great resource if you have a little time.
It is a bit different in the way it puts together family trees but it does afford you the chance to find information many times that you didn't get from one of the other big genealogy research sites.
Another resource if you are researching ancestors in Georgia. That state seems to have done very well in maintaining records of all types.
A comprehensive, categorized & cross-referenced list of links that point you to genealogical research sites online. A genealogy starting point for more than 15 years
This site is owned and operated by The Church of Jesus Christ of Latter-Day Saints (Mormons). It is an extremely helpful resource and it is the free arm of the Mormon records keepers. The Mormons have to date, scanned more than 3 billion records which they have contracted to receive from the U.S. government. Do not overlook this valuable resource.
As of this writing, Find-A-Grave has more than 146.3 million graves in their database. It's completely free and an invaluable resource particularly in "sourcing" your records.