I try my best to use as much OSS on my phone as possible (I compile my own OS from CM), but it's really hard to get everything
If you want to use a faux-taxi or similar service, Lyft, Sidecar, Flywheel and Uber all need the Google Play Services to work.
The sad thing, is that Sidecar is available on the Amazon store, but since there's no way to explicitly state the dependency of an application on Google's libraries, it will just crash at installation/runtime with a segfault (due to not being able to load a .so)
Only after going back to a device with the Google services I realized that you can actually use Uber from your mobile browser (it's at m.uber.com, but if you visit uber.com from your mobile there're no prominent links that point to the former)
https://developer.amazon.com/post/Tx14BH5AW0NG41K/Amazon-Map...
granted, this might not be as fully-featured as Google's (I never used either), but given the existence of Openstreetmap and other efforts like the Nogapps project http://forum.xda-developers.com/showthread.php?t=1715375 there should be enough manpower to build a solid alternative.
It's a bit sad that Amazon is not capitalizing/building-on/improving OSS, but it's even more sad that 99% (random estimate) of the (western?) Android apps are constraining themselves to run only on Google-licensed devices
edit: nvm i see it now. For ref it is at https://github.com/microg