If Cricket refuses to add WAP to your plan, head to wap.cricket.motricity.com, try to go anywhere on that page, get an error saying you must sign up for mobile web, click "Sign Up for $5 a month" and bam, you've got web on your account without having to say a word to anyone.
Be advised, however, that by doing this, you could be cheating yourself out of some features. As an example, I used to be on the $45 plan and wanted web. I could either add web from the site for $5 or I could upgrade to the $50 plan that included web and unlimited directory assistance (not that I've used it once in my life, but...).