PayPal makes selling and buying safer (and easier) with credit card transactions. If you register your credit or debit card with PayPal, essentially you'll be using your credit card but under the PayPal protections.
99% of the time you will need to use Paypal. Paypal has a guest feature to let you pay without being a member. I can't remember how many times you can use this without getting a paypal account.
Most sellers do not have their own merchant accounts and I don't know of a way to filter in only the auctions that accept card directly.
Note, you must be 18 to use either eBay or Paypal. To filter out underaged users, Paypal does NOT accept prepaid cards of any kind.
It is solely the seller's discretion.
You can pay with PayPal, Skrill, money order, check, by post and virtually every way a seller might want to. PayPal is swift and featured on eBay.But I prefer Skrill (unfortunately not available on all "local" eBay like ebay.it, ebay.co.uk, etc.) just because it is as swift and has overall smaller fees. But in the end you have to accept the fact that especially in international orders, the electronic wallets work the best, and fastest. You don't want to wait 2 weeks for a payment to clear then another few for item you bought to arrive...and then realize it's the wrong colour.
Pretty much 100% of the sellers use Paypal now. It is to everyone's advantage. You don't want to be giving your credit card number to some total stranger in another part of the country.
It is free for you to join, and you can use the credit card # you currently have.
Most sellers will accept money orders if you ask. Some of the larger ones won't waste their time with you, though. Money orders take time to process/clear.
Bear in mind if they decide to rip you off you have very little recourse because eBay will not cover you under buyer protection. You may have to file a claim in small claims or contact the local PD in the seller's jurisdiction.
do you always need a paypal to pay stuff on ebay or can you use your credit card/debit card??? Does it depend on the seller??