Gulp is Germany's market place for freelancers. Unfortunately only in German ("Gulp in English" only brings a short overview of the company).
To see what (technical) qualifications earn/cost you how much (based on contracts brokered via Gulp), just enter at "Fachlicher Schwerpunkt" the expertise (comma-separated, e.g., HTML5, Python) and select on the right whether they're AND ("und") or OR ("oder").
Below you'll find statistics, where "Stundensatz" is the hourly rate. For your orientation:
"Entwicklung der Stundensätze" = development of hourly rates;
"Verteilung der IT-Erfahrung" = years of experience;
"Verteilung der Stundensätze" = distribution of hourly rates;
"Postleitzahlengebiet / Land" = zip code / country.
As a rule of thumb the rates in the North (e.g., Berlin) are lower than in the South (e.g., Munich), but so are the costs of living.