Re: Using Default Cart. How do I set up a button of MY OWN?
Welcome to the Forums.
When you use PayPal buttons created in your PayPal account you do not need a separate cart. This is how it works: you create your PayPal button in your PayPal account, you copy and paste the button code to your website, when your customers shop on your website and click on the PayPal button it will add the product/service to PayPal's shopping cart and the customer will check out with either a credit/debit card or log into their PayPal account.
If you choose to use a third party shopping cart there would be a setting within your shopping cart to select PayPal as one of your payment methods. When you say "my cart icon has to be hosted on some secure site in order to attach Paypals code to it," I think what you are talking about would be an SSL certificate - this makes your website secure, you would need an SSL certificate to checkout using PayPal. You would purchase an SSL certificate from your hosting company.