This app was mentioned in 2 comments, with an average of 1.00 upvote
I don't think $30 is one of the topup amounts they offer - are you sure you have the right app?
https://play.google.com/store/apps/details?id=nz.co.adriley.paymypark
https://itunes.apple.com/us/app/paymypark/id1039736488?ls=1&mt=8
We have that in New Zealand. You can even pay for parking too.
https://play.google.com/store/apps/details?id=nz.co.adriley.paymypark&hl=en