For anyone wishing to cheat in Endless Space Alpha release, you can do that using generic memory editor like CheatEngine (I used 64 bit version of it), or ArtMoney. Search for a Exact Float value that is shown TopLeft above empire management icon. To change value for filtering down buy something, or end your turn. Money is very powerful in this game, you can finish big projects and build armada of ships in a single turn.
It does work. Do it exactly as described in the OP. Sometimes you will end up with a single value, sometimes with two. If it's the latter - the one that changes quicker when you buy something is the one you want.
I've done exactly that. I get no values matching my current amount of dust.
I think the problem is because it doesn't add dust in whole numbers, but adds it in decimals (7.3 dust per turn instead of just 7) and the displayed amount of your dust isn't true. Sometimes the value displayed next to the empire management button is one off from the value displayed under current empire status. That's probably from a rounding error.
I don't know how to use cheatengine well enough to search for numbers that aren't integers.