Before you click the Paynow button there should be an option (in smallprint) that says "change payment method". Click on that and then select "Pay using a Credit Card" from the list of options. Remember, your bank account or funds remaining in your Paypal account will always be the default option because Paypal doesn't want you to use a Credit Card because they're afraid of chargebacks.
Just show up at their doorstep with cash in hand wearing a "I Buy Coins" t-shirt. Can't get any safer than that.
I'm old fashioned. I pay by check most of the time. HOWEVER.... I only buy bigger dollar items from people I know. I also ask a lot of questions before I even consider bidding. It's worked for me for 9 years but I really don't bid that much anymore. ...and Oldman. I do ACCEPT cash!