I have so far come across 1 pilot who works completely for free, no pay, no salary, for a paid commercial operation. I have heard of many others doing the same, but I have only ever come across the one who actually did it. His justification was simple, "I am getting multi command" and last I heard he had moved onto a regional.
The next category of working for free I have come across is the pilot on the contract with ABN agreement who do extra duties. I can think of numerous pilots who worked 40+hrs for operators doing non flying duties, including using their IT and other experience to complete tasks for the operator for no remuneration of course, which to contract out would have cost big $$$. They would get a few flying hours a week, but never significantly more than everyone else, It worked out to be sub $7 per hour for the 40 hour week. (If they were happy to work for that amount then good luck to them)
Then there is the things people would do to get ahead, those few extra hours a month or quicker progression, this is common in other work places that I have been in as well, so not as exclusive too aviation as the other two. I'm sure most of you who have worked in GA would have seen this.
The other one I noticed is with interviews/door knocking, plenty of guys/girls seem only too happy to offer free services before they are offered a spot or check ride. This in my opinion only makes you an easy target to be taken advantage of in the future. By all means try be competitive, but whats the point in not being paid to do other duties, if you do this you have even less chance of actually getting paid to fly.
I have only worked for 1 year in GA and would hate to know some of the things the guys who have been around for a long long time have seen. Dont get me wrong though, I have no issue with going above and beyond, or doing that little bit extra to help out. but some of the things that happen in GA are ridiculous.
I understand that its highly competitive, and operators will exploit this, which I have seen occur on many occasions. Ultimately its up too you as an individual to keep a minimum standard for yourself, what you will work and not work for, just remember that its a small industry and many will remember you for what you did and did not do.
Happy Flying!