"This offer entitles you to $10 off the pre-coupon purchase price (excluding postage costs) on Eligible Items during the Offer Period, when you spend $80 or more (excluding postage costs) in one transaction using a credit card or debit card (Visa, Mastercard, Amex, Discover). Multiple items may be purchased in 1 transaction total (up to a maximum of 10 items per transaction)."
"You can only use the redemption code once during the Offer Period."
No time limit mentioned but
"eBay reserves the right to cancel the offer at any time."