Per person. Park fees, hut/camping fees, rescue fees, and crew wages included.
Marangu is the only Kilimanjaro route with hut accommodation the whole way, which keeps costs down and appeals to people who would rather not camp. It is also the shortest standard route to the summit, at six days.
That speed is the trade-off. Six days gives less time to acclimatise than the seven-day Machame or eight-day Lemosho routes, and Marangu has the lowest summit success rate of the three as a result. It suits trekkers who are confident in their altitude tolerance, are on a tighter budget, or genuinely prefer not to camp — not people looking for the easiest way up. The mountain is the same difficulty regardless of route; only the acclimatisation time changes.
As with every route, park fees, hut fees, rescue fees, guide and porter wages, meals, and group equipment should all be included in the quoted price. An unusually cheap Marangu quote is usually cutting porter wages or safety margin somewhere, not finding a genuine efficiency.