definite article [in the rebate]

[ansonman]

I have made up the sentences below.

(1a) We have started our rebate program for our valued customer. To express our appreciation, we would like to offer our customers $150 in the rebate on most of our merchandise.

(1b) We have started our rebate program for our valued customer. To express our appreciation, we would like to offer our customers $150 in a rebate on most of our merchandise.

Most of my non-native speaking friends think the definite article "the" is correct. A few of my other friends think "a" is correct. What is your opinion? Thanks.

[Alan]

Neither.

--> as a rebate...