Selecting Pretzel24 as payment method redirects to https://go.przelewy24.pl/ where in turn you choose between different banks. I guess it is a Polish service for direct bank payments?
I misread it as Pretzel the first time and couldn't resist, especially after clicking the page gave me a 'NOT FOUND' error. I assumed it was some sort of payment system.
"przelewy" means "wire transfers" in Polish: https://en.wiktionary.org/wiki/przelew Nothing to do with pretzels. :)