Using 2 gift vouchers at same time..?

I have two $20 gift vouchers for dymocks book store, so If wanna buy a book for like $40, will I be able to use both at the same time?Using 2 gift vouchers at same time..?
I think you can use as many gift vouchers as you want in one transaction. After all, technically the store has already been paid, so they have no reason to object.Using 2 gift vouchers at same time..?
with 40 bucks you can go play paintball
yes the cashier will know what to do to make the purchase complete
yes you can!

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