This introductory offer is for three days only.

本试销优惠只为期三天。

《牛津词典》

Provide a special introductory offer to them and likewise reward your current clients who helped.

FORBES: The 10 Steps To Finding More Customers

Unless the introductory offer specifically includes new purchases, any purchase made with the new credit card will be at the ongoing interest rate.

FORBES: Tips On Transferring Your Credit Card Balance To Another Issuer

Unlike many travel rewards credit cards, the Miles by Discover Card carries no annual fee for the life of the card and has an introductory offer of 0% APR on purchases and balance transfers for up to six months.

FORBES: The Best Travel Rewards Credit Cards, April 2012