Paypal has different fees depending on whether it's bulk payments or not.
The 30cents I mentioned was the company's fee - it could also be an admin fee that they charge and that they're absorbing the rest of the fee in their commission structure. They are using PayPal.
Humble Store charges s a 2% fee, up to $1 maximum per payment, when using PayPal.
In contrast your Payout fees are 19.5%
Smashwords did for ebooks what you've done for games - only a few steps further as they also distribute them to major stores - I've received small payments from them - but how the 1c minimum works I don't know. However, they also have a minimum purchase amount of 99cents - so after commission they probably never have a balance go less than 60 cents. But any fees are absorbed in their commission so it has to be quite low.
https://www.smashwords.com/about/supportfaq#Royalties
$1.99 book price
$0.59 retailer commission (Apple Store)
$0.19 Smashwords commission
$1.21 what I got paid - from Smashwords via PayPal.