Sheesh, I deal with that crap. I'm a graphic artist and it's my job but I also freelance on the side. I dropped my last client last year because they were idiots who didn't want to pay for work.
Last year had this client asked me for a website and asked "How much would it cost to get a 5 page website up?" I give them my usual rate of 500 for a basic website of 5 pages, 700 if you want content written, and any work that get's past 15 hours will be billed for $50 per hour with a minimum of 1 hour. They agree. a month in the project I was at the 17 hour mark, logging my hours as usual, and now about 8 pages into the project. I send them the bill for $950 bucks and they refuse to pay. While refusing to pay, they forgot, as the few clients who worked with me (or any other freelance designer) has done, to change the password on their host. 2 minutes after telling me they won't pay, i logged into their godaddy account (if they used any other source it would have taken 45 seconds...god I hate godaddy) and their website magically disappears. 3 minutes later they're asking me where their website is and I said "What website? I only publish websites that have been paid for." Then they try to threaten me with this legal BS and I promptly sent them every email I have from them highlighting maybe 10 spots where they said "Can't wait to pay you when this site is up" or something close to as well as my comments of "As a favor to you since you are a friend of a clients and they recommended me to do your work, as soon as it's done Ill put it up and you can pay me after." They eventually mailed me a check 3 days later. Never called them since.
They called me a month ago asking for a logo that they will pay me for. My standard rate on a logo = $60 for 3 samples. I send them 3 samples as I stated and two days later I get asked for 2 more and to keep it at the same price and asking to make changes to their website that would take more than 2 hours, with no charge.. Haven't sent them ****. I hope they are dumb enough to try and use any of the ones I sent so I can call a C&D on them and eat their heads.
GODDAMNIT I love idiot clients.