Rather than hook it up to your bank account, hook it to your credit card.
If something goes wrong with a transaction and you get ripped off, you can file for a PayPal chargeback. If the seller who has ripped you off can't prove to PayPal that he sent the item to you, and IF he still has a balance with PayPal, they will credit you the money your seller pilfered. BUT, if they can't get the money back because his paypal account is empty, you can contact your credit card company and file a credit card chargeback in order to get your money back. So using your cc thru PayPal will double your chances of recouping your losses on bad deal.
If you pay through your bank account, your chances of getting your money back on a fraudulent transaction are slimmer than slim. If PayPal can't get the money back from the seller, you have nowhere else to turn.
On the other hand, if you are going to sell stuff on ebay, THEN you need to have your PayPal account hooked up to your bank account because you need to be able to transfer the balances in your PayPal account to your bank account.
Having said all of this, I highly doubt that people who sell knitting stuff on eBay are going to rip you off. But just be aware that your cc can protect you in the even that you ever get into a bad deal on ebay.