Whilst I validate my code, I know a lot of coders these days don't value the w3 validator as much (reading through various dev blogs anyway). I think it's fine if something doesn't validate but still works in all browsers efficiently, and doesn't validate for a logical reason.
Microsoft should pay coders everytime someone writes a site that works in their POS browsers, the amount of extra work required to make up for their mistakes is a major pain in the arse.
For a quality, xhtml/css coding $150 for 3-5 pages isn't too bad. It's hard to say exactly without seeing the design because obviously one design mite take longer to code than others. Also consider everyone has theri own definition of "quality coding".