I use paypal because it is pretty much the only payment option ebay allows every since they purchased paypal. You can use it for any online store though, just have to set it up. The buyers do not have to have or setup a PP account in order to pay either. For an online store you would basically use PP as a 3rd party payment processor. The buyer can pay via most common credit cards or use their bank debit cards. However you would have to do your research or contact them to see if they will allow payments for for what you are selling. I know back in 2009 / 2010 accepting payment or paying for anything vape related was strictly prohibited. It was due to the strict regulations in regards to online sales of tobacco products. I am thinking they have changed their guidelines though, because now you can search "MOD" on ebay and get over 200,000 results. Search RDA and you get around 17,000 results. Because they are being sold on ebay they are being paid for via paypal. You can even find e-juice and while most is 0 nic there are plenty that offer it with nicotine. Like I said more than likely you will have to contact them and maybe even get approved or something.
If paypal is a no go then I would just set up an account at usps.com. It is free and you pay and print directly from their site.