We travelled overland from Abu Simbel in Egypt to Khartoum in 15 days / 14 nights in November 2016.
Travelling in Northern Sudan may not be easy and comfortable, but it's rather straightforward and the opportunities for spending money were quite limited. Altogether we spent a little more than 800 €, not including the bus in and the flight out of Sudan, but including all other fees and visa costs. Nearly half of that amount went directly to the government, covering visa and similar fees and sightseeing. Accommodation, food, and transport on the other hand were almost negligible.
On average we spent 11.65 € per night on accommodation: In many places in the north we paid less than 10 € for a double room, going up to 20-30 € in Khartoum. Some of the cheaper rooms had shared bathrooms, not always running water or no running water at all. Especially in the north the rooms were not very clean or particularly inhabitable. We had brought an inner tent which served as a stand-alone mosquito net with the additional benefit that anything living inside the mattress would stay outside our bed (because we put the mattress on the floor and the tent on top of the mattress). In a few rooms we encountered cockroaches. In Atbara and Khartoum there was a greater choice of accommodation, and some hotels even had some sort of Wifi. In most places however there were no nicer rooms available, while cheap beds in the courtyard (only an option for men) cost around 2 € per night.
Food was very cheap, but of quite limited variety. Breakfast usually consisted of a falafel sandwich (sometimes with egg) and for dinner we shared a bowl of foul (cooked beans) with fresh flat breads, with additional salad on lucky days – all of which cost us about 2 € at most for the two of us. Add some fruit or yoghurt and the occasional dish at a Lebanese or Ethiopian restaurant, and coffee and bottled water – in total we spent in Sudan less than 7 € per day on food and drink. As the country is ruled by Sharia Law, alcohol is not available at all and thus does not figure in the expenses.
In total we spent 181 € on transport, although public transport is quite cheap in Sudan (but also rare, slow and cramped). The complete trip from Wadi Halfa to Khartoum by bus and minibus with several stops along the way would have cost around 60 € for both of us, including some hitchhiking on the back of pick-up trucks for which we paid a small contribution. Occasionally we walked a few kilometers. Additional costs were 100 € for a 4x4 hire for one day (with driver) to visit the sights of Mussawarat and Naqa, and some boat and tuktuk hires to visit some other out-of-the-way archaeological sights (around 20 €).
We applied for the Sudan Visa in Aswan in Egypt, apparently one of the easiest and cheapest options to receive a visa, but still it did cost 50 $ per person. In Sudan we had to pay (in Sudanese pounds) an additional fee of 25 € per person for registration and some obscure fee we never figured out what it was for (we got an official receipt, though).
The biggest chunk (191 €) of our budget were entrance fees to the sights. Even smaller archaeological sights cost 10 $ per person and the three highlights near Khartoum (the Bagrawiah pyramids, Musawarat and Naqa) were 25 $ each, per person. As the sightseeing was the main reason for our visit to Sudan, we did pay the exaggeratedly high entrance fees. We were lucky that there was nobody to collect the fees at some smaller sites in the north, and in some other sites we were able to bargain the price down. The only sightseeing bargain was the splendid National Museum in Khartoum at 0,12 € per person.
Compared to an organised tour, travelling independently in Sudan is still quite cheap, even if you include the expensive sightseeing.