We have created a system called StickyPayments which will allow you to create invoices, take payments and pay the technology fee.  To use StickyPayments through the Checkout pages you would first need to create (if you do not have one already) and link an account with Stripe.

Linking your StickyApp Account With Stripe

Once you have linked your account with your Stripe account you can create checkout pages.  Using Checkout pages your clients will pay via the builder and the technology fee is taken out automatically and the remainder is deposited back into your bank account.