I have recently signed up under the recommendation of a friend. Like LaRue said it is a bidding war, but the site said they would only allow 3 trainers to bid on the training job.
I’ve only placed a bid on 4 and on 2 I was refunded my credit (money) as they give the potential client 48 hours to respond to your bid.
There is also a way to get credit and change your status from “Bronze” to “Silver” to “Gold” standing, by answering additional questions, updating your profile, pictures, etc.
I hope this helps and good luck!