If it's an option, you're better offf using a traditional AMEX (even blue card). Debit cards (including Cobalt) are like paying with cash. YOU HAVE NO ABILITY TO DISPUTE AND REVERSE A CHARGE. With priceline if your hotel isn't in the zone you bid on (rare but Sheryl's website has some examples) or there is a dispute as to the quality star rating of a hotel you have given up your opportunity to dispute (and reverse) the charge. More importantly if the vendor goes out of business credit card customers usually get the charges credited back, people who pay with cash,checks and debit cards may have to wait until the bankruptcy court sorts it out. I know Priceline guarantees the room payment with their credit card, but I'm not sure when it is literally paid to the hotel. With a credit card but if Priceline goes under or restructures you have recourse with a debit card much less. THIS APPLIES TO ALL PURCHASES NOT JUST PRICELINE. IF YOU HAVE A CHOICE, USE A CREDIT CARD (EVEN IF YOU HAVE TO GET A SECURED CARD) Just assess the risks.