I am playing around with wordpress and a few plugins. Say I have something called "Shopping Cart" and I delete the page. Then I recreate it, I can't have the old URL back. I get domain.com/shopping-cart-2 and I want the old one back. How can I do this?
You are asking about the slug of a page.
Please check the trash and remove the previous page from trash as well. Afterwards you should be able to re-use the previously used slug.