I think it was twice.
The prophet Elijah anointed a man named Hezael. Hezael was the king of Aram.
David was anointed as king by Samuel.
Saul was anointed by Samuel as the first king of Israel.
The last Judge who anointed two Kings was the prophet Samuel. He anointed Saul as the first king of Israel and later anointed David as the second king.
Twice once as a boy and then as a king. David was anointed 3 times. In 1 Samuel 16:13 by Jesse. In 2 Samuel 2:4, by the men of Judas as king over the house of Judah; and in 2 Samuel 5:3, as King of Israel.
Olive oil.See also the Related Link.More about King David
King David.
Saul, the farmer boy of the Old Testament Unable to find Saul being anointed king and prophet. The man Christ Jesus was anointed prophet, priest, and king, but I can find no other reference to any other person. Saul was only anointed king, as was David and Solomon, etc.
Mizpah
There is no such thing in the Tanach. All Jewish kings were anointed with oil as part of their being made king.
The bible does not give his age, but he was the sun of Kish, and it was the prophet Samuel who anointed him as the king of Isa real. Samuel also anointed David as the king of Israel.