You'll essentially be getting the lens and the SD card for $300. A great value for your money.
As of this post, there were only two left at this price. If you want one, you should pull the trigger on this deal now.
More GH4 bundles from the Adorama store on eBay here:
And, if you miss out on these Adorama deals, there are some pretty good GH4 bundled deals at Amazon too :)