About an hour of a senior developer's fully-loaded cost.
To be clear, 8hrs/day, 40hrs/week, 50weeks/year is about 2,000 hours. Are you really saying that "senior developers" make 250USD * 2,000 = 500K USD? 250K is more like it, and only in very high cost locations -- Silicon Valley or NYC. More like 150K in rich countries, but not the richest city. Hell, 100K EUR can get you some very good developers on the European continent.