There is an automated waiting list for lots for sale at Online Land Sales. If you wish to be notified of the availability of a lot that is not currently available, you can have an email delivered to you if the lot becomes available in the future. Simply go to the listing for the sold lot and select the link that says: Email me when Back-In-Stock.
To find sold lots, look at the sold subdivisions in the state. Or, if there are still lots being sold in that subdivision, go to the bottom of that subdivision’s page, and you will see a link to the already sold lots in that subdivision.