While tickets are still selling from the official outlets, yours will be worth less than face value due to the matter of authenticity. Perhaps as low as 50%.
Your call, but good timing on Ebay after the tickets have all sold out, will ensure that you get the best price. Set the auction to end on the preceding Thu at say 10pm, with a next day special delivery for them to be posted on the Frday am and arrive at destination on Saturday. Auction winner to pay for the postage costs, which I'm sure you can find out and make clear on the auction page.
You got them for nothing, so whatever they're worth or whatever you sell them for is somewhat irrelevant.
Why not give them to a charity?