Record of any sale of land would have been recorded in "Pantebøker." Notes from the LDS Family History Library catalog give this information -
"These mortgage records give information about real estate, conveyances, mortgages and other transactions of properties. Contracts, agreements, and deeds are also recorded in these books. The panteregisters are extracts of the mortgage records. These records are for Idd og Marker judicial districts which include these places: Degernes, Aremark, Øymark, Idd, Berg, and Fredrikshald (now Halden) in Østfold county."
The catalog indicates that LDS has copied the Pantebøker which include the Berg area for the years 1738-1873 to microfilm which can be ordered and sent to any Family History Center around the world.
The Digitalarkivet website has started to scan Pantebøker and Panteregister (indexes) and made some available online for that area (into the 1950s) though and perhaps you can find what you want right there.http://www.arkivverket.no/URN:tl_read?lang=engelsk