you can create a paypal for free as long as you are 18.
The money you get from Ebay will be transferred to your paypal account. But you cant transfer it to any bank unless you added a bank account.
But you can use the money in paypal to buy anything online.
If its faulty, then the guy might ask for a refund, and if he does, and you say no, then he might file a dispute where Paypal will decide by listening to yours and his story, and who ever is wrong, has to accept it, like if you are wrong, he is going to get all his money back, and about $10 to ship the product back to you.
Sometimes it might be best to say something like, not tested so no returns, or pulled out of an working hardware (if it was working).
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