When I started Poker Copilot in 2008, I paid $250 + fee to run a design competition on CrowdSpring. Most entrants were underwhelming. But at the time it was much cheaper and easier than the main alternative, which was using the services of a designer.
In 2016 there's a much better option: Logojoy - you may have seen it indirectly yesterday on Hacker News.
For $65, you get a quality logo to choose out of many designs generated "using artificial intelligence, genetic algorithms, and a few other fancy technologies."
I'm putting my money where my mouth is: I used Logojoy today to create the logo for my upcoming new SaaS product.
(File this under "persistent downward price pressure")
Edit: Maybe hold off before buying from this site. They seem to be crumbling under an avalanche of traffic.