Used to be checkouts for things like hotel wifi passed the price as an unvalidated URL param. All you had to do was change `&price=9.99` to `&price=0.01` and yo

Used to be checkouts for things like hotel wifi passed the price as an unvalidated URL param. All you had to do was change `&price=9.99` to `&price=0.01` and you got cheap wifi.