I don't think Paypal would be much help, as they are owned by eBay. I paid with Paypal balance, so I'm pretty much at their mercy on this one.
Ebay/Paypal will usually side with the buyer, and when a seller lists an item there are choices that he makes relative to handling, such as turnaround time, whether or not items are returnable, who pays return shipping, etc.
I think that you have a strong case here, it is not a question of condition (item was listed as "Excellent" but it is barely "Good") or (seller said it is working but I say it isn't) since you clearly received a different item than the listing showed.
If I bought a Black and Decker circular saw and received a Black and Decker jigsaw, that is not a minor discrepancy.