payment cost

Paypal charges 4% from the amout of the payment and 0,35 cents. Can I let my customers pay this?

No. There is no option for that in PayPal. You would have to raise your prices to integrate the costs of paypal. Or, e would have to add a way to have costs in the options of payment methods which is not possible at the moment.

Ideal, a payment method from the Netherlands, costs 0,99 per transaction. Maybe you can add a feature in the future. With the shipping method you can add a price as well.

One thing I want to say: Great shopping component. Great work!!

There are cheaper Payment Service Providers than the one you've selected for iDEAL transactions.... Do a search on internetkassa.