Sudan is the biggest country in Africa.
Visas are required by all except:
- Citizens of Syria
- Passengers of an on-ward flight (within 6 hours).
Otherwise tts visas are not very easy to acquire. Your best chance seems to be to try to get it in Cairo, where it costs 100 US$. Another option is in Ethiopia, where they are less happy to give the visas, but the costs are "only" 60 US$.
- Your passport should not contain evidence of a visit to Israel.