I found two football clubs in Kassel who have their own women's team.
The more professional seems to be Hessen Kassel.
I did not find anything about a members fee.
Contact for the women team is: http://www.dasbesteausnordhessen.de/uebersicht.php?p=17&c=77
The mor fun oriented club with a women team is Dynamo Windrad.
Member fee for one year is 90€, but you can have 2 free trainings.
The training times you find here:
contact info for this club:
They have a statement against racism on their homepage.
Seems to me like a good sign, that refugees are welcome.