Sorry to hear you're now dealing with eBay/Paypal. Good luck with that!
Secure sites, HTTPS vs HTTP, are becoming more common as the cost comes down and the push is stronger to get more of the Internet to encrypt. The cost of the security certificate used to be close to $1,000/year or more. However, just because a site uses HTTPS, it doesn't mean they're always legit. One thing to look for on a site are 'security seals'. These are usually tied in to whomever is actually doing the credit card processing and are 'renewed' every time the page displays. If the merchant, for some reason, doesn't renew their security evaluation, the image won't display. For example, here is what appears on our site:
An advantage of using a service such as Authorize.Net, Paypal (which I will NEVER do), etc. is that the processing is fully automated and the merchant never sees the customer data. Unfortunately, I don't think eBay will let you use anyone other that Paypal.
Now, as to why I will never use Paypal... We used to use both eBay and Paypal. We got turned off on eBay/Paypal by the large number of scammers. The final straw was when a buyer claimed they never received their order. The package was sent with a 'Return SIgnature' request, meaning that they had to sign for the package. They did. We had the signed receipt. We had a letter from the USPS verifying the authenticity. eBay/Paypal told us that no amount of documentation would invalidate the buyers claim. As a result, the yanked several hundred dollars out of our account and we were left with nothing, And this was before they started changing all of their policies to completely favor the buyer with no recourse for the seller. Yes, that was years ago. Yes, they may have changed their ways. No, we will never use them again.
Of course, there were also the impatient 'buyers' that would send an E-Mail at 3:00am asking the color and dimensions of a vase that was clearly stated in the online description. And then they would send another note at 3:15am wondering why we hadn't answered yet. It might have been tolerable if we we getting better prices, but we weren't. We were actually getting less.
I'll get off of my soapbox now.