That's precisely what I'm talking about. There's a huge difference between working at what "the market" deems you're worth, and working at what you tell the market you're worth. Most engineers do the former because they feel talent should speak for itself and I poo-poo things like marketing, positioning, and, God forbid, self-aggrandizement.
I know for a fact that high quality PHP coders routinely get $50-75/hour and true bad ass motherfuckers can get $100-150/hour. I say this as someone who has tried to find good quality talent and see about 90+% failure rate in the technical interview, and I suck at PHP.
If you're some monkey on RentACoder that "knows" PHP along with ASP.Net, J2EE, ASP, Python, RoR, CSS, MySQL, XHTML, blah blah blah -- i.e. someone that knows a lot of acronyms but doesn't do enough projects to really understand any single field in depth -- then expect $15-20/hour.
If you focus on one area exclusively and become a master of it -- the kind of guy that can write a good book on the subject -- then you can command a shit load more.
This is true of CSS as well -- and you think PHP is fucking commodity?! Any monkey can hack enough CSS to get things looking correctly on like that one version of IE6 on Win2K or whatever, but the real bad asses -- the Dan Cederholms and the like -- don't work for $50/hour.
But if you simply look for job offers and then apply, then you're dealing with HR monkeys and you will lose. I have a reasonably positive reputation as a game programmer, and the few times I've sent resumes to game companies that have posted job offers I typically won't get any interest because HR tossed my resume since I don't have a degree.
Now I could bitch that that's unfair and fucked and resign myself to taking whatever shitty job comes my way...or I take the strengths I have, realize that the system in place isn't going to give me what I want, and change how I approach the system to my benefit.
Stuff like this is talked about over at http://www.gamingmercenaries.com (currently ugly, sorry -- stock WP theme)