PayPal is expensive, but convenient. For transactions between Canadians we can use Interac for free, but if one party is outside the country and you want to make a "Card Not Present" transaction, you need to either use a Credit Card (Debit Cards are not the same product in the US versus other countries, but you might be able to use a Debit Card as well) or something like PayPal.
Selling on eBay is massively skewed towards the buyer's protection, but there are ways to protect yourself if you are a seller as well. For example, if your listing title says "For Parts or Repair Only" then the buyer cannot make a claim for non-function, appearance, etc. If you instead indicate the condition in the text of your auction, you are screwed if the buyer complains about appearance, function, suitability, etc. Just one example.