I have used this - it is awesome. Missouri Death Records ... actual death cert More than 6.8 million records can be accessed through Missouri Digital Heritage, including the collections of the Missouri State Archives, the Missouri State Library and more than 50 institutions from across the state.
United States Census Resource - You can download the census rolls and search them for your ancestor(s). It has helped me find family when I could not find my ancestor(s) listed on indexed files on familysearch.org or on ancestry.com ... I love this site! :) - Oh, and it is free! :)