Multi Vendor, Q: Taxes and transaction fee

Hi,



Im going to start a Multi vendor store soon, but I really need to know these things first befor I decide to create one.



Question 1: When and product is sold by a vendor, taxes have been added to the product already (as far as I know, correct me if im wrong). Do I need to pay any additional taxes when I will send out the commision to the vendor each month?



Question 2: Is there any transaction fees? If so, how much are they for each payment method there is?



This shop will be based in Sweden, if that helps.



Regards,

Jörgen K.