This was $35 a week ago when I ordered and now it is $30. The way I figured, at worst I overpaid for a slightly bulkier USB powerbank to keep in the car, with the upside of being able to potentially save me a big headache!
Reviews available from the Amazon US site. Most seem positive (it works!) and the build quality seems pretty good to me.
It has lower current so if your battery is dead dead it might not work. However if the car just died on the road it should work very well.
Ebay selling for about $56.
10800 mAh
USBC (5V)
QC 3.0
In case you're wondering.