I have Destiny, including the Taken King, downloaded on PS3. What is the least I must buy to play it on PS4?
Solution 1:
If you bought Destiny on release, you may be able to upgrade. Check this article for details.
Anyone who bought Destiny digitally before Jan 15th of 2015 could upgrade for free, but if you purchased after that, you're SOL. Then there was a brief trade in window in September, but that was at GameStop.