If I received an expensive gift from one of my clients (money), do I have to declare it as an income, is it taxable???
Gifts received from a clients are not considered to be revenue earned during normal course of business. Generally, it should not be included in your business income as it does not involve a revenue generating activity.
This is a very delicate question as it touches more than the tax aspect. It is highly unethical to receive a monetary gift from clients as it may imply payment for products/services or preferential treatment expectation.
Regardless of which products or services you provide and what industry you are in, it is important to not get biased and make sure gifts do not change the way you provide your services. Make sure you are not involved in any sort of corruption or other illegal actions.