Hello everyone!
I'm pleased to announce that you can now set sales taxes for your online store! Simply head over to Settings > Store > Settings and choose your country and state and enter in the current tax rate. From that point on, if you receive any orders from within your state, tax will be charged to those customers but not to outside orders.
You can read more about it through our help article:
http://www.jimdo.com/help/store/us-sales-tax/
Enjoy!