"website that entirely uses Perl"

What, no HTML? I doubt there is a "subroutine" that would do what you want, and watch out for things free--in the end you might be sorry you didn't pay for it. There are four kinds of code resources: free, stolen, opensource, and for-hire. Why don't you hire one of the good monks here to write it for you. If these ads are going to generate income, then might be worth the investment.