No, this is not my line, I just jump in and offer help when I think I can.Keep in mind census records are notorius for errors, but still a good way to start a search.
Have you used the LDS website?http://www.familysearch.orghttp://www.familysearch.org That is where I got the 1880 census info.Now, that is extracted from the hand written record and keep in mind it can be read incorrectly, too.
The nice part about the FamilySearch version of the 1880 is it is very user friendly.It will often bring up names of "similar" spellings where other indexes have to match exact spelling, even if they spelled it wrong and you have it correct.(^_^)
The 1900 census info I got from online Heritage Quest, it shows actual digitized handwritten record. I have access to HQ through a local public library.Only libraries can subscribe to HQ.HQ does not have all the censues indexed, yet.Check with public libraries in your area, see if any have Heritage Quest.
Family History Centers (litte branches of the big library in Salt Lake City) have a subscription to Ancestry.com and you can use their computers, volunteers will show you how to access information from Ancestry.Ancestry has an everyname index for the 1870 and 1930 censuses, but you do have to match the spelling exactly.So, if they abbreviate Charles to Chas and you spell it Charles, the record will not come up.Does it ever get easy?LOL