Hi Jvaclavik,
I’ll start with a disclosure that I’m one of PushApps co-founders - and after that I’ll recommend you to check our Push Notifications service.
We have some clients who use ionic so you wont be the first.
You shouldn’t pay so much for a good push server, and you can see it in our pricing
http://www.pushapps.mobi/
If you have any question I’ll be happy to assist you, but you can find it all in our documentations
http://wiki.pushapps.mobi/
Thanks,