PayPal and Stripe charge a fee to process payments. Every time an attendee registers for your tournament this fee will come out of the money they pay.
The processing fee does not go to smash.gg in any way, running tournaments on our platform is completely free.
You can add a processing fee, as well as additional fees (like VAT, for example) on the Payments Setup page. The fee is a percentage + a $ amount. So enter 5 if you'd like the fee to be just 5%, or you can make it 3% + .30 to match PayPal and Stripe fees exactly.
Each additional fee you add will appear as a separate line item at checkout.
Here is what the fee will look like when an attendee is registering with only the processing fee applied.