People are kind enough to buy you something, so don't refuse.

People are kind enough to buy you something, and you don't want to refuse.

You can say that you don't usually use these things, so good and expensive, it's also a waste to give them to you.

First of all, you should say how good his gift is. And make him think you don't deserve something like this. It's easier to refuse. This is also a way to refuse to accept gifts from others. Will receive very ideal results. Give it a try! At least it won't offend people.