This is one of the sad results of our materialistic society. Doing something nice for someone else is searched for hidden meaning (ooh, they must want something).
Worker co-operatives are possible, and they do exist in the US. There are several in my city. You may enjoy All Things Co-op (Democracy @ Work)
https://www.youtube.com/watch?v=9yTZi2bMa5I&list=PLPJpiw1WYdTN5quYUdzB3yF7nMa3bheh1&index=5