All of July, The Taken King, the Digital Collector's Edition and the Legendary Edition were all 50% off. Sale's over, I'm afraid.

This could actually be an interesting experiment....

If you never purchased TTK, but purchase ROI, would you be locked out of anything?

I have not really thought about it.

So, I know there is the "everything that was released edition" that newbies can buy if they have never played destiny before, but now that there is regular DLC I wonder if it is cumulative, meaning if you skip a DLC, but get the NEXT DLC, would you therefore be able to access what you missed previously?

I would assume "yes" to a point. Let's say I never bought Dark Below or House of Wolves. If I bought the everything edition to catch up, I could play the stories, but it's too late to experience the Blades of Crota of Pack of Wolves public events.....

I suppose that is the trade off. You wait, you get to play (most) of the content for cheap, but the gear is obsolete.

Come to think of it, I never got a husk of the pit.... so I guess I'll never get the Necrochasm.