how long will founder pack be out?

@full951  Here is the PS4 US LInk: https://store.playstation.com/en-us/product/UP0006-CUSA12540_00-FOUNBU0000000000

and this is apparently fot XBOX Live US : https://www.microsoft.com/en-us/p/apex-legends-founders-pack/brj6h1j098wr?activetab=pivot:overviewtab

There als also direct links for Germany and Spain. So, it might be that you can't buy a Founders Packs when you're living somewhere else.

Regarding if the pack is worth it or not:

When you're ready to support Respawn Entertainment, yes. If you think you can get dozens of legendaries and maybe the Heirloom Set, most likely no.

If you  think you can get dozens of legendaries and maybe the Heirloom Set BUT actually don't get mad when you're getting nothing out if it, yes.