Yes, there are! In StubHub International, you can enjoy the promo codes, vouchers, gift code, etc... You can check the expiration date of each type of discount in the StubHub Wallet section (in your profile).
In case you have a gift code or a promo code, you can add it in your account. Go to your Profile and click on StubHub Wallet. Then, scroll to the final of the page to add the code and click on Add.