Those who haven’t bought The Dark Below expansion are locked out of this week’s Heroic and Nightfall strikes in Destiny.
Bungie has decided to allow only those who bought The Dark Below access to this week’s Heroic Nightfall strikes. It’s unclear at this stage if this is just for launch week or if it’s how it will be going forward.
Here’s an image showing this week’s Heroic strike:
The weeklies are the only guaranteed source of Strange Coins in Destiny.
Bungie has yet to comment on any of this as of this writing.