Hi.

In the situation where a web site have the following problem:

1) No clear use of URL. Exemple:
www.website.com/01/002/pages.aspx?sku=0&id=99

2) No semantic
Not HTML compliant, no use of H1 (all P class="")

And my goal is to have a better search engine ranking. What would be
the best action knowing that budget limitation leave me only one of
the following possibility?

A) Change all URL. Exemple:
www.website.com/target_audience/section/product/specification.aspx

B) Change all template to be XHTML Transitional compliant and use CSS
to remove presentation tag from the code. Use of h1 to help search
engine identify title, sub-title and content.

C) Take all this money and buy AdWords. =)

Please include case study or article to support your answer.

PS: Sorry for my english.

If you are running Apache, you may be able to use mod_rewrite to
rewrite the URL into something more SE friendly.

Or you could change to a different shopping cart =)