Don't lure with discounts: not only do you undermine the value of the product by showing that you can offer it at a lower price, but you also train people to come only for favorable conditions.
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Give a gift. The most effective way is to give something related to the goods and services.

A hairdresser? Make a hair mask.

A restaurant? Pour in the branded tincture.

A printing house? Print a run of business cards as a gift.

Just remember that the gift should not be at a loss for you. If you consider the effectiveness of the discount to be 20%, then the gift should cost half of this discount.
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People love freebies, but they especially love nice gifts. And if this gift leads to a customer signing up for one of your services, you'll be a double winner