Sounds like it'll be a book set - PHB, MM, DMG, XGE, TCoE, Volo's & Mord's is my guess.
I'm also thinking it's a set, but probably not that many. As a complete guess, it may be just the 4 expansions, or the core with a setting. 7 books for $170 would be a great price; 4 sounds more realistic.