BEFORE Step 1: Buy Sirius XM Gift Cards and load them into your account for the package you want. Then go through the steps, and when it comes time to pay, they'll see that you have money there and deduct it. NO CREDIT CARD.
Best Deals that I've gotten:
-Select - 6 Months for $30.00, with fees and taxes, about $45.00
-All Access - 12 months for $119.00, with fees and taxes, about $155.00.
Best Buy, or bestbuy.com had the cards. If you get them online, you can post the amounts to your account right away. Any left over money is used for the next time you renew