Whenever possible, I try to replace links to ancestry.com and americanancestors.org with links to the same source on a free site. familysearch.org links are sometimes just a link to an index or database, you have to look elsewhere for the source. Often these sources are available on another web site. Here is a list of free sources that may help:
Each source is grouped by location.
The most comprehensive free site is https://familysearch.org
We can probably recommend other useful free sites if you tell us which countries you are researching.
For Scotland you can search for free, but need to buy credits to view images on: https://www.scotlandspeople.gov.uk
For Ireland, the government site which is free is: https://www.irishgenealogy.ie/en/