Having 3 star deck,
It took me 200~ hours of botting indolent imperial to get Fenrir.
So, if you want to pay $15 and spend 200~ hrs botting, then you can decide if it's worth it or not. Of course you can shorten this time by doing the logs for MGP.
The bot works, though running to the NPC has issues, just plant yourself there and go for it a little at the time.
It was the most effective method for me, so it was worth it IMO.