Is it possible to get the pc/java version of Minecraft for free after buying it from the Windows 10 store?
Is it possible to get Minecraft (pc/java) for free after purchasing windows 10 version?
No, Microsoft and Mojang have stated that the versions are different, so if you want to play both, you have to pay for both.
They are essentially different products.
It is now possible to do the opposite: If you buy Minecraft Java, you can get a free copy of the Windows 10 edition here.