labor of love
something done for personal pleasure and not for money
The man's painting is a labor of love and he does not expect to make any money from it.
Deep Sea Mysteries And Oddities That Will Leave You Baffled
One of the more commonly referenced deep sea creatures, the anglerfish has an appendage coming out of its forehead with a light on the end. It uses this to lure prey in before devouring them with its over sized mouth.