Can be either -- human behavior can't be divided into good/bad or black/white. we are complex beings with complex motives for our behavior.

the complexity of human nature is often divided into simple answers that help us explain the events in our life as well as the actions we perform. unfortunately, we are all victims of complex processes that go on that help us perform actions. in some cases giving to others is a moral and social victory. not only do we feel better about ourselves but we have acheived a social victory because we are recognized for our unselfishness. if we are looking for an economic return then we are motivated but something other than self interest. so if self interest is to be recognized and gain either socially, morally or economically, then it is in our self interest.

I think that giving can be an act of self intrest if somehing is wanted in return without a previous agreement. For instance, your little sister gives you a candy bar expecting a cookie in return, but she never asked for one.
On the other hand, there is selfless giving, and this can be simply letting someone ahead of you in line, or, as I plan to do should I die anytime soon, to donate your organs, because what benifit are they to you once your dead? And they can be a tremendous help to someone else... So in the sense of the question, you could say that its not "giving" unless it is selfless, otherwise its trading

If you give to others, you will get something yourself that cannot be measured.

Its just giving to be a nice person. nothing wrong with that