This pack contains Rock Band 4 base game, download code for the new expansion and a wireless guitar controller. I saw it for this price in my local GAME store earlier today as well as online. It's only in stock for the PS4 and the Band Kit isn't in stock for either platform unfortunately.
This seems like a good price to me as Amazon is listing it at £99 and it is hard to find even the base game guitar bundles for this low of a price atm. Factoring in that the expansion costs £20 on the PSN store, I would say this is well worth it.
My first deal post so sorry if I missed anything obvious.