Nairobi has a wide variety of tourist hotels, from backpackers' campsites Upper Hill Campsite off Hospital Road to five-star establishments such as the Norfolk Hotel. There are a number of other guesthouses that offer private rooms both with shared bathrooms and self-contained rooms for between 1,000/- and 4,000/- per night. As long as you don't mind basic accommodations, there is no need to spend more than $100US per night on a hotel or hostel. In less touristy areas, lodging can be found for as cheap as $5USD per night. Be wary of bed bugs, though - it may be advisable to purchase insect spray and bring along your own sheet if you plan to travel very cheaply. In addition, the international Intercontinental and Hilton chains are also represented as well as a number of very highly regarded local chainsSerena and Sarova Hotels. Small boarding and lodging establishments are ubiquitous in downtown urban areas for low cost, although these are rarely safe as they are located in high crime areas.
Homestays are increasingly gaining popularity. Part of the reason is that one is able to experience Kenyan culture in a deeper and more meaningful way. Most homes charge about $20 per night inclusive of meals. Some may include laundry on that price.
People staying longer-term may rent accommodation; prices range from estate-agent 'international style' rentals at $150+ pw, to privately arranged furnished apartments, from $50-$100 pw, to 'local' style accommodation, usually unfurnished, in a price range from ksh5-7000 per month with windows, water, electricity, down to ksh500 per month with no windows, no electricity, loud neighbours, mosquitoes, shared access to a tap. To arrange privately rented accommodation, you'll need to ask around - cab drivers, shopkeepers, market traders, could all save you the estate agents' fees.
