There are certain jobs that are great for the fiverr or 99designs type of job. They are cheap little gigs with a very limited scope. I use fiverr all the time for removing the backgrounds from photos. People can do them fast and cheap. I trust them thoroughly to be able to do this job.
This is the important thing with freelancers – trust. If we try to hire someone we don’t trust, we end up doing all the hard parts of the job. We hire a graphic designer we don’t trust, we end up doing all the important parts of the graphic design.
I’ve seen a bunch of people try to use 99 Designs to get themselves a new logo. They get images from designers, then they ask their friends which ones they like. The goal of a design is not picking something that you or your friends like. The goal is solving important communication problems. This approach is like choosing a doctor based on which one will be the most fun.