Coupons system

[fceruti]

Hello:

 

We have a store (www.ergowear.com) that needs a cuopon system to promote the sales.

 

We need a single cupon to be sent to mailing lists of potential clients (hundreds or thouthands of emails).

 

Something like saying: "Hello: if you buy before December 15th, you will get a 10 dollar (5%) discount using this coupon : ZXLXLKJ09SD2L"

 

There should be an expiration date of the coupon (valid until XYZ date).

 

Of course any additional functions are welcomed.

 

Help please...anybody.