I have it on good authority that sometime after the Mother's Day special runs out next week, the digital versions of SAWBONES, BLOOD OATH and BADLANDS will increase in price to roughly $7-$9/book. That's still a great deal for four hundred pages of awesomeness! But, if you can get them for the next week for less, why wouldn't you? Pre-orders should stay at the lower price.
Go forth and stock up! SUMMER VACATION IS AROUND THE CORNER!
Kobo | Nook | Google Play | iBooks
Why am I not linking to Amazon? This is why.
Until Amazon treats authors and publishers fairly or clarifies this new policy, I refuse to link to them. You are welcome to buy from them, but know that there's a very real chance that authors will not receive royalties from third party sellers. If you want to support authors, make sure to buy the books SOLD BY AMAZON and include Prime. Shipped by Amazon doesn't mean the same thing.
Digital copies are the same price regardless of the app you use, and all of the above apps are free.