If you place a bid that's below the reserve price, you'll see a 'Reserve not met' message. This means that even if you're the highest bidder at the end of the auction, you won't win the item.
Sellers can lower their reserve price during the auction, or make a Second Chance Offer once it's ended. This means you may still have a chance to buy the item – we'll send you a message if either of these happen.
Sellers don't have to reveal what they've set as the reserve price. Unless they state their reserve price in the listing, you won't know what the reserve price is until you meet it, or bid above it.