There used to be only a slow train and a fast but bumpy bus between Wadi Halfa and Khartoum. Both have been replaced by a newly paved road and a fast buses that run the evening and next day after the ferry arrives. The latest bus price is 90 Sudanese Pounds ($39) and can be bought at the bus station on arrival.
Getting a bus from Khartoum to Wadi Halfa is a little more difficult because the bus companies are trying to operate under the government’s radar to avoid taxes and regulations, so they change their departure point regularly.