Before I get into the issue of other record availability, I should note that Ancestry.com and other large online databases serve a valuable function of "one-stop-shopping," they are the large supermarkets and discount box stores of Internet genealogy. For some of the same reasons I shop at Costco, I also use Ancestry.com. Time is money and availability is valuable. This post is not intended to be a criticism of Ancestry.com, but an illustration of alternative availability for some of the records.
One other comment. You might find the exact same documents on Ancestry.com, freely available from other sources, but you should also be aware that there may be even more material than is in Ancestry.com outside of their databases.
Now back to the examples. If you dig down into Ancestry.com you will find a lot of very interesting collections. Ancestry.com has a general category of records called "Stories and Publications". In that category, they have a further category of "Stories, Memories & Histories." If you click on this link, you will get a further category called "Oral Histories & Interviews." A further filter lets you select a geographical area, such as "USA." At this point, you are down to 12 or so collections of records. The first one that came up on my search was 2,370 "U.S. Interviews with Former Slaves, 1936 -1938." If you read the description of this collection, you will see that it has the following description:
Ancestry.com. U.S., Interviews with Former Slaves, 1936-1938 [database on-line]. Provo, UT, USA: Ancestry.com Operations, Inc. This collection was indexed by Ancestry World Archives Project contributors.
A Folk History of Slavery in the United States From Interviews with Former Slaves, 1936–1938. Vol. 1-17. Federal Writers’ Project of the Works Progress Administration microfilm publication SCM 000 320, SCM 000 321, SCM 000 322, SCM 000 323, SCM 000 325, 5 rolls. Library of Congress, Washington D.C.First of all, this is a document in the public domain as a U.S Federal Government publication. So does this document exist outside of Ancestry.com? A quick Google search on the name of the so-called collection shows that you can download a searchable copy of this publication in PDF format for free from many locations on the Web. See one example, http://manybooks.net/titles/wpa1944619446-8.html
In addition to downloadable copies, this particular book is entirely searchable through the Library of Congress. Now, just because I can buy some of the things at Costco elsewhere does not stop me from going there to make purchases. But I may not want to drive all the way to Costco and it is always nice to know that I can buy the same stuff at other stores.
Another important note. The Library of Congress not only has the transcripts of many of the slave narratives, but it also has actual audio recordings of the former slaves. See http://memory.loc.gov/ammem/collections/voices/
Here is another, but opposite, example from the next collection down on the list of the search I made above; Transcriptions of Ellis Island Oral Histories. Is this document available elsewhere? Well, they are available for free at Ellis Island, but I don't think I will be going there any time soon. This is a copyrighted collection (how that works is an interesting issue) and Ancestry.com seems to have a lock on the collection except for Ellis Island.
Is it worth looking elsewhere (or do I just get in my car and drive to Costco?) There are two points here; you should look for the collections' subject matter in other locations on the Internet and you should look for additional material about the subject, not in Ancestry.com.