Is there a list of whats on sale ? They dont seem to be advertising theres a sale.

Keep an eye on 

https://www.androidpolice.com/tags/app-sales/

I use Pushbullet that pings me every time they post

this ones looks like a bargain, now only $2.99

https://play.google.com/store/apps/details?id=com.quantumsoftwarestudios.expensiveapp

1101:

 

this ones looks like a bargain, now only $2.99

 

https://play.google.com/store/apps/details?id=com.quantumsoftwarestudios.expensiveapp

 

$4.89 for me.

xpd:

 

1101: this ones looks like a bargain, now only $2.99
https://play.google.com/store/apps/details?id=com.quantumsoftwarestudios.expensiveapp

 $4.89 for me.

Maybe the bold part applies to you? 

Edit: Discounted from $599.99 to $4.89

reminds me of that Iphone app ruby or sapphire that cost $500 and did nothing

Got monument valley - looks pretty slick. Any other good ones people would recommend?  I saw the list a couple of days ago in relation to IO, but wasn't sure what was actually worth getting