Is there a legally mandated filing fee and/or deposit?

There is no specific regulation onwhether to have fees on election related appeals or not. However, the court didnot ask for it in 2010 election and this is what we observed there. Here is aquote from Carter Centre final report to justify our answer:

“Results appeals to the NationalSupreme Court

Rather than randomly drawing judges,the chief justice of Sudan handpicked two electoral panels of three justiceseach, selecting none of the court’s six women. .. Court fees are nominal.“

Carter Centre final report on Sudan’s2010 election, page 52. Link: http://www.cartercenter.org/resources/pdfs/news/peace_publications/election_reports/FinalReportSudan-Apr2010.pdf