This probably isn't the kind of answer you're looking for, but - for me - the answer would be volunteering services and mentoring.<p>It's not done with the motivation of earning money (otherwise it wouldn't be volunteering). But the network connections made and karma - if you will - that has come back resulting in job offers, people taking the time to teach me new things that ended up resulting in new opportunities, etc. have been numerous.<p>And while not money, I've made a lot of wealth of friendships in the same way who have helped me through tough times (some financial).