From what I experienced recently, i got an email from Agoda with voucher code 10% off (SAVEMORE) Expired in 30 April 2017.

You must click on the specific link given in the Email and direct you to Agoda website. Search those hotels you prefer with "PROMO ELIGIBLE" tag which allow you to key in Voucher Code at Payment Page.

I tired to search on the usual way which you guys did, type agoda url address in google and link me to agoda website. there is no way you can key in the code at the payment page.