Cheap dual-port car charger with 18W USB-PD
Also has 7-segment LED input voltage display.
If you need QC3+PD, their regular price of $10 is not bad either: https://www.kmart.com.au/product/18wpd-+-qc-3.0-car-charger/…
They also have a $2 single-port USB-A 2.1A charger. (just throw out the badly designed bluetooth earpiece that comes with it.)
( previous post at $5 for the latter https://www.ozbargain.com.au/node/616843 )
Enough for surface?