Get a debit (prepaid) card from your bank. Many banks today offer "Web prepaid cards" (usually a Visa or MasterCard). Some even give them without additional membership fees if you're a student. Coupled with online banking/mobile banking (or even without it, if you live near the bank
) you can have the funds transfered and ready for buying in a matter of minutes. And it's perfectly safe, as long as you only transfer the funds when you're about to buy something...
You don't even need Paypal or other "online wallet" services that way, as Visas are accepted pretty much everywhere for online shopping, and if you only keep a small amount of cash on it, even if you get hacked you only lose a few bucks...