Upon arrival, most foreigners find Cairo to be a surprisingly affordable city. The conversion rate between common currencies rests at about 1 USD to 16.7 EGP, and 1 € to 19 EGP. Average monthly expenses on a relaxed budget—excluding tuition and rent—can typically run around $300. One may live well on a smaller amount of money (~$200) if he or she chooses, or eat out at cafes and restaurants more regularly and live on broader budget ($400+). Traveling expenses and excursions in and around the city can also factor in to your monthly expenditures. Like any major city, Cairo offers both expensive and cheap options for every aspect of life, just as it has an extreme spectrum of social classes and income distributions.
For a more comprehensive breakdown of average living expenses, visit this blog post on budgeting.