I could certainly do this for you but firstly need a few questions answered.

What kind of deadline are you looking at?

And why only a $50-75 budget? I personally would quote at least $150 but hey who am I to talk? ($30x5hours)

Which form of XHTML? In other words, does the client care about semantic markup (XHTML can be built with div/span alone, or headings, paragraphs, and so on). Accessibility? what about slight cross-browser inconsistencies?

It's is all very well asking for "XHTML and CSS" but what you get when asking for those things can be very different from what you expected.

Thanks,
Peter