Itch only takes 10% by default and you can set that to any percentage you want, all the way down to 0%, in your settings page.
The low payout was probably due to the $3 fee to pay for the tax interview service, which is taken out of your first payout. You can check how the money was split in your dashboard.
(Ofc, the credit card/PayPal fees ($0.30 +2.9%) are here too, but that happens on Patreon as well.)