PayPal is now offering PayPal Plus, and new credit card that will feature 0% interest on purchases until March 2007.  This is especially helpful if you make your business purchases with a credit card, because you can even make off-season purchases and hold onto the items until it's time to sell them, without accruing interest on your credit card!  Here's the announcement:
 
This week PayPal is introducing the new PayPal Plus Credit Card. PayPal Plus is a new MasterCard that can be used online and offline, anywhere that MasterCard is accepted. Additionally, the PayPal Plus Credit Card features a rewards program free with your card that applies to all of your purchases. Wherever you make a card purchase - online or offline - you'll earn points towards eBay Reward Coupons. See our information page to learn more.
http://pages.ebay.com/paypal/buyercredit/buyer/promotion/?ssPageName=CMDV:AB

As an added bonus, cardholders can take advantage of a special introductory offer - 0% APR on purchases and balance transfers until 2007. This limited-time offer is good through August 31, 2006, and will automatically appear on eBay items over $50 as long as sellers accept PayPal and have not opted out of displaying PayPal Buyer Credit messages on their listings. This promotion is completely free of charge to sellers (regular PayPal fees apply).