Ancestry probably has the most images online, but if you want to start some searching before paying anything, familysearch.org can be a good place to start. They have indexes of the census, but not images for all years. They also have many other records of marriages, deaths etc. - some include images. It all depends on the place & the year. I have found some images there that are not on ancestry.
A lot in the US can determine on where they lived. There are state & county sites that can may have additional information. When BMD Certificates were required varies by state (as does the price). Some were registered at the town or county level prior to the state requirement.
findagrave.com can be useful in cemetery searching, but it depends on what volunteers have entered so not all burials are included.
I would also keep in mind the US board on this site. It's been my experience you will receive more timely & complete answers from the great researchers here than most message boards based in the US.
Good luck with your search!
Lisa
