In Germany, the average Software Dev salary is about 50k€/year. That's a total payroll cost of about 60k€/year after taxes, social security etc., so around 300€/workday. Add some money for office space, equipment, overhead, etc, and adjust by factor of two in either direction depending on location and role.

Of course if you hire a freelancer, prices are very different and 1500€/day is very reasonable.