I agree, having a form instead of manual request through support is a good idea.
I don't think the author should be allowed to set any ridiculous price without moderation. It can damage trust for buyers and business for sellers. An author still has the freedom to directly stop selling an item if they don't agree with the pricing. Codester lets authors price as free as possible. We only step in when a pricing does some kind of damage. Like already mentioned +95% of the time the author suggested pricing is no problem.
Also allowing an explain/comment field for any price change would be a good idea.
Thanks for the feedback!