Bundle the 2 short stories together and offer them free on Kindle. Since you won't be just doing this as a temporary promotion, Amazon will probably charge you for the service. But it will be an excellent promotion for your two books. You can offer the ebooks for $2.99 each.

Hugh Howey still offers the first part of Wool for free, and look what it's done for him.

Wool Omnibus Edition by Hugh Howey

This is the story of mankind clawing for survival, of mankind on the edge. The world outside has grown unkind, the view of it limited, talk of it forbidden. But there are always those who hope, who dream. These are the dangerous people, the residents who infect others with their optimism. Their punishment is simple. They are given the very thing they profess to want: They are allowed outside.

This is the omnibus edition. It collects the first five books (which are almost like volumes of the same book) into a single release. It's about 550 pages.

Got my copy and pimed it out to all my buddies. Now let me finish Wool and I'll get going on it.