I've been freelancing full-time, including editing. I'm actually preparing to release a training program on freelancing (becoming self-supporting, then building a work team, and then finally creating a self-sustaining business around your skills). My rates vary according to the difficulty of the project, how many hours it will take to do it, and whether I intend to put my own time into it or hand it off to a team member. One thing that I do -- and I've noticed that a huge percentage of freelancers don't -- is that I tell the client straight out if I'm going to outsource it to a team member. We get into a three-way Skype conversation in which I introduce them to the person who will be working on the project, and assure them that I quality-check everything to ensure that it meets my own standard of quality. As you can imagine, the contract also varies, though it does have several points that are consistent -- which I will be typing up into a hub for you tonight or tomorrow morning, because that is a LONG explanation.
At any rate -- feel free to contact me through my profile with specific questions that I will gladly write hubs about, or just for general freelance discussion. I've been looking for other freelancers out there who are potentially interested in mastermind/accountability type groups, so please do feel free to strike up a conversation :).