Most of the books in G.M. Ford's Leo Waterman series are on sale for $2 each at Amazon US as part of their "20 Kindle Books for $2 Each" sale. The sale says it's good through 9/30/2014.
You can just go to the sale (
http://www.amazon.com/gp/feature.htm...cId=1000858781) and pick them out, or you can search on "GM Ford", and then sort by price, and you'll see the ones which are available. Most of them have been on sale or free before, but if you missed one or two, or are new to this and haven't seen them on sale/free before, here are a bunch of them!
The ones I see for $2 are:
Who in Hell is Wanda Fuca?
Cast in Stone
The Bum's Rush
Slow Burn
Thicker than Water
Chump Change
Spoiler about the first book: